A rifle with a weight of 30 N fires a 5.0-g bullet with a speed of 300 m/s. (a) Find
the recoil speed of the rifle. (b) If a 700-N man holds the rifle firmly against his
shoulder, find the recoil speed of man and rifle.

Answers

Answer 1

_______________________________

Notes:

1grain = 64.8mg

1newton = 100g

= 300 m/s (speed)

= 30 × 100

= 3,000g (rifle mass)

= 5-g × 64.8

= 324mg (bullet mass)

= 700 × 100

= 70,000g (human mass)

= 70,000g + 3,000g

= 70,300g (human + rifle mass)

A) Newton's 2nd Law of MotionM1 V1 = - m2 v2Vr = - mb ÷ mrVb = - (324 ÷ 3,000) 300= 32.4 m/sB) Newton's 2nd Law of MotionM1 V1 = - m2 v2Vr = - mb ÷ mr Vb = - (324 ÷ 70,300) 300= 1.39 m/s

_______________________________


Related Questions

estimate the work you do to mow a lawn 10m by 20m with a 50 cm wide mower. Assume you push with a force of about 15 N.

Answers

Answer:

W = 6000 Joule

Explanation:

Work is defined as force times distance

W = F * d

We know that F = 15N, we just need the distance (d)

Imagine you have a square lawn with length of 10 m and width of 20m. So, we want to know the the distance you have to travel to cover every square meter of the lawn.

The width of the mower is only 50 cm = 0.5 m.

This means that you have to go back and forth 40 times to cover 20m (lawn width), with a distance of 10 m (lawn length). So,

d = 10 (meter) * 40 (times) = 400 meter

Therefore:

W = (15) * (400) = 6000 J

A 1.3 kg mass is attached to the left end of a meter stick. The meter stick is then balanced on a fulcrum as shown. If the mass of the meter stick is 0.2 kg and its center of mass is located at its geometric center, how far to the left of the stick's center of mass (‘d' in the figure) should the fulcrum be placed to balance the meter stick? Provide your answer in centimeters.

Answers

The fulcrum to balance the meter stick should be placed 8.33 cm to the left of the center of mass of the meter stick, under the condition that the mass of the meter stick is 0.2 kg and its center of mass is located at its geometric center.

In order to balance the meter stick with the 1.3 kg mass placed to the left end, we have to evaluate the distance ‘d' from the center of mass of the meter stick to the fulcrum.

The given center of mass of the meter stick is found at its geometric center which is at 50 cm from either end of the stick. Then the mass of the meter stick is 0.2 kg.

We can apply the principle of moments to evaluate this problem. The principle of moments says that for an object in equilibrium, the summation of the clockwise moments about any point must be equivalent to the sum of the anticlockwise moments about that point.

Let us consider that moments about the fulcrum. The clockwise moment because of the weight of the 1.3 kg mass and is stated by (1.3 kg) x (d cm). The anticlockwise moment is because of the weight of the meter stick and is given by (0.2 kg) x (50 - d cm). Since the meter stick is balanced, these two moments should be equal.

(1.3 kg) x (d cm)

= (0.2 kg) x (50 - d cm)

Evaluating for‘d’,

d = 8.33 cm

Hence, the fulcrum should be placed 8.33 cm to the left of the center of mass of the meter stick.

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state in terms of m, u and v ,the change of momentum of the object

Answers

The change in momentum of the object in terms of its mass, initial velocity, and final velocity is 5 kg m/s.

The change in momentum of an object can be calculated using the formula:

Δp = m * (v - u)

In this case, the mass of the object is 0.5 kg, the initial velocity (u) is 0 m/s, and the final velocity (v) is 10 m/s after 3 seconds of uniform acceleration.

Substituting these values into the formula gives:

Δp = 0.5 kg * (10 m/s - 0 m/s)

Δp = 5 kg m/s

Therefore, the change in momentum of the object in terms of its mass, initial velocity, and final velocity is 5 kg m/s.

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--The complete Question is, A 0.5 kg object is initially at rest. It then accelerates uniformly for 3 seconds and reaches a velocity of 10 m/s. Calculate the change in momentum of the object in terms of its mass (m), initial velocity (u), and final velocity (v).--

A flashlight bulb is connected to a dry cell of voltage 5.25 V. It draws 15 mA (1,000 mA = 1 A). Its resistance is

2.5 E2 ohms
3.0 E2 ohms
3.5 E2 ohms
4.0 E2 ohms

Answers

____________________________________

C) 3.5 Ω

Ohm's Law: R = V / I × 10= 5.25 ÷ 15mAh × 10= 3.5 Ω

____________________________________

Four point masses 2kg, 4kg, 6kg and sky are placed at the corners of Square ABCD of 2cm long respectively. Find the position of centre of mass of the system from the corner A.​

Answers

The position of center of mass is, 1 cm right, and 1.4 cm above the corner A, of the square ABCD.

The respective coordinates of masses, on corner ABCD, are:

Corner A: 2kg (0,0)Corner B: 4kg (2,0)Corner C: 6kg (2,2)Corner D: 8kg (0,2) ... (assuming the not given data as 8kg)

Let the coordinates of COM(center of mass), be, Xcom and Ycom.

Therefore,

Xcom = [ ∑([tex]M_{i}[/tex] x [tex]X_{i}[/tex]) / ∑([tex]M_{i}[/tex]) ] , and

Ycom = [ ∑([tex]M_{i}[/tex] x [tex]Y_{i}[/tex]) / ∑([tex]M_{i}[/tex]) ]

That is,

Xcom = [ {(2x0)+(4x2)+(6x2)+(8x0)} / (2+4+6+8) ]

Xcom = (20/20) cm

Xcom = 1cm

Similarly,

Ycom = [ {(2x0)+(4x0)+(6x2)+(8x2)} / (2+4+6+8) ]

Ycom = (28/20) cm

Ycom = 1.4 cm

So, the position of center of mass is, 1 cm right, and 1.4 cm above the corner A, of the square ABCD.

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You are an astronomer and are making observations about a
visible but faraway galaxy. In 2-3 sentences, describe what evidence you could gather to gain more information about (1) the galaxy's elemental
composition and (2) its motion relative to the Milky Way Galaxy.

Answers

To determine the elemental composition of the faraway galaxy, would use spectroscopy to analyze the light that is emitted or absorbed by the galaxy. This technique enables me to determine the types of atoms and molecules that are present in the galaxy, providing insights into its elemental composition.

To determine the galaxy's motion relative to the Milky Way, would use the Doppler effect to measure the galaxy's redshift or blueshift. This would enable me to determine whether the galaxy is moving away from or towards us, and at what speed, providing information about its motion relative to our galaxy.

It could also look for any gravitational lensing effects, which could indicate the presence of massive objects that are influencing the galaxy's motion.

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2. Suppose the sled runs on packed snow. The coefficient of friction is now only 0.12. A person and sled weighing 650 N sits on the sled and it is pulled at a constant velocity across the snow.

A. Draw FBD.
B. What is the combined mass of the sled and person?
C. Determine the frictional force value.
D. What is the value of the force needed to pull the sled?

Answers

Answer:

Explanation:

B.  W = mg     m = W/g = (650 N)/(9.8 m/s²) = 66.33 kg

C.  Ff = μN = (0.12)(650 N) = 78 N

D.  F > 78 N

Note:  Brainly doesn't provide drawing tools, so I can't help you with the FBD.  But here's a try at it: N = normal force, F = applied force, W = weight of person + sled, Ff = force of friction,  ⊕ (person and the sled)

       N

       ↑

Ff←   ⊕  →F

       ↓

      W

Help. Don’t mind the highlighter answers i don’t know if there right

Answers

A convex lens is also known as a converging lens because it causes the incident light rays that are travelling parallel to its main axis to converge.

A convex lens has an outward curvature. In comparison to the edges, the middle is thicker. The rays of light bend in the direction of one another when they travel through a convex lens. On the other side of the lens, the rays only come together at one location. Convex lenses amplify or provide the impression that objects are larger.

The image is upside down in relation to the original object and is also oriented inverted from right to left in the convex lens. The term "inverted" refers to such a position. The real image formed by the convex lens is inverted.

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4.
The "force" that moves electric charge carriers through an electric circuit is
a superconductor
resistance
An
10
a
MacBook Air
s
8
current
voltage
DII
8
A
EMA
4
F11
F12

Answers

Answer: Voltage

Explanation: Not really sure what all that other stuff is after your question...

The "force" that moves electric charge carriers through an electric circuit is ________.

An electric charge carrier moving through a circuit is a charged particle (usually electrons). The force that pushes it is called an electromagnetic force, commonly known as EMF.

Between atoms, EMFs are what attract electrons from one atom to another to form bonds. Likewise, In a circuit, the EMF is the driving force, which is known as voltage.

Superconductivity refers to a state in which these charge carriers travel at a specific voltage with no resistance, meaning no energy is lost. However, this isn't an independent force, so it's incorrect.

Resistance affects the circuit by slightly dampening the flow of charge carriers. Resistance commonly comes in the form of temperature or simply a characteristic of the material through which the circuit flows, so this is incorrect.

Current merely refers to the flow of charge carriers through a circuit in a given time window.

(Think of a circuit as a water pipe. Current is like the speed of a specific amount of water and Voltage (or EMF) is the pressure in the pipe. The higher the pressure, the faster the water flows. Resistance is anything in the pipe that impedes the water flow)

If you have a potential energy of 57 J. Now double your height, what is your new potential energy?

Answers

The new potential energy you will have, given that your height is doubled is 114 J

How do i determine the new potential energy?

The following data were obtained from the question:

Initial potential energy (PE₁) = 57 JInitial height (h₁) = HNew height (h₂) = double of initial height = 2HNew potential energy (PE₂) =?

The new potential energy can be obtained as illustrated below:

PE₁ / h₁ = PE₂ / h₂

57 / H = PE₂ / 2H

Cross multiply

57 × 2H = PE₂ × H

Divide both sides by H

PE₂ = (57 × 2H) / H

PE₂ = 57 × 2

PE₂ = 114 J

Thus, from the above calculation, we can conclude that the new potential energy is 114 J

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The current-potential difference graph for a resistor is a straight line as long as the is constant. What is the missing word?​

Answers

Answer:

Potential Difference = Voltage =  Resistance * Current

As long the resistance is a constant the PD will be a straight line when plotted against the current.

A boy of mass 60 kg and a girl of mass 40 kg are together and at rest on a frozen pond and push each other apart. The girl moves in a negative direction with a speed of 3 m/s. What must be the final momentum of the boy?
A. 100 kgm/s
B. 120 kgm/s
C. -120 kgm/s
D. 40 kgm/s

Answers

Answer:

B. 120 kgm/s

Explanation:

The initial momentum of the system is zero since the boy and the girl are at rest. When they push each other apart, the total momentum of the system remains conserved. Since the girl moves in a negative direction, the boy must move in the positive direction with the same momentum to keep the total momentum of the system zero.

Let's assume the final momentum of the boy is p. According to the law of conservation of momentum,

(initial momentum) = (final momentum)

0 = p + (-40 kg)(-3 m/s)

0 = p + 120 kg m/s

p = -120 kg m/s

Therefore, the final momentum of the boy must be 120 kg m/s in the positive direction, which is answer choice B.

Ans

According to the law of conservation of momentum, the total momentum of the system before and after the interaction must be equal. Initially, the momentum of the system is zero since the boy and the girl are at rest. When they push each other, the girl moves in the negative direction with a speed of 3 m/s. Let's assume that the boy moves in the positive direction with a speed of v m/s.

The total initial momentum of the system is:

P_initial = m_boy * 0 + m_girl * 0 = 0

The total final momentum of the system must also be zero since there are no external forces acting on the system. Therefore:

P_final = m_boy * v + m_girl * (-3) = 0

where m_boy = 60 kg, m_girl = 40 kg, and v is the final speed of the boy in m/s.

Solving for v, we get:

60v - 120 = 0

v = 2 m/s

Therefore, the total final momentum of the boy must be:

P_final = m_boy * v = 60 kg * 2 m/s = 120 kg m/s.

So, the total final momentum of the boy must be 120 kg m/s.

A small block with mass 0.0400 kg
is moving in the xy
-plane. The net force on the block is described by the potential-energy function U(x,y)=(5.50J/m2)x2−(3.70J/m3)y3
.
Part A
What is the magnitude of the acceleration of the block when it is at the point x
= 0.40 m
, y
= 0.50 m
?
Express your answer with the appropriate units.

Part B
What is the direction of the acceleration of the block when it is at the point x
= 0.40 m
, y
= 0.50 m
?
Express your answer in degrees.

Answers

The magnitude of acceleration at the given point is 8.04 m/s², and the direction of acceleration at the given point is 38.5° below the negative x-axis.

To find the magnitude of acceleration at the given point, we need to calculate the force acting on the block using the potential-energy function and then use Newton's second law, F=ma, to find the acceleration.

The force acting on the block can be found by taking the negative gradient of the potential-energy function;

F = -∇U = (-∂U/∂x)i + (-∂U/∂y)j

where i and j are unit vectors in the x and y directions, respectively.

Taking the partial derivatives of U(x,y) with respect to x and y, we get;

∂U/∂x = 11.0 J/m² × x

∂U/∂y = -11.1 J/m³ × y₂

Plugging in the values x=0.40 m and y=0.50 m, we get;

∂U/∂x = 1.76 J/m

∂U/∂y = -1.39 J/m

Therefore, the force acting on the block at (0.40 m, 0.50 m) is;

F = (-1.76 J/m)i + (-1.39 J/m)j

Using Newton's second law, F=ma, we can find the magnitude of acceleration:

a = F/m = ([tex]F_{x}[/tex][tex]F_{y}[/tex]/m₂ + [tex]F_{y}[/tex]₂/m₂)1/2

= [(1.76 J/m)2 + (-1.39 J/m)2]/0.0400 kg

= 8.04 m/s2

Therefore, the magnitude of acceleration at the given point is 8.04 m/s².

To find the direction of acceleration at the given point, we need to find the angle between the force vector and the positive x-axis.

The angle θ can be found using the formula;

θ = tan-1([tex]F_{y}[/tex] /[tex]F_{x}[/tex])

Plugging in the values of [tex]F_{x}[/tex] and [tex]F_{y}[/tex] at (0.40 m, 0.50 m), we get;

θ = tan-1(-1.39 J/m / 1.76 J/m)

= -38.5°

Since the force vector is in the third quadrant (i.e., both [tex]F_{x}[/tex] and [tex]F_{y}[/tex] are negative), the angle θ is negative. Therefore, the direction of acceleration at the given point is 38.5° below the negative x-axis.

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A mango hanging on a tree possesses a potential energy of 150 J.If the mass of the mango is 5kg Calculate the height of the mango from the ground take (g = = 10 m/s²​

Answers

Answer: 3 meters from the ground

Explanation:

gravitational potential energy= mass*height*acceleration of free fall(g)

150=5*h*10

h=150/50

h= 3 m

5.
The mass in a moving spring system has no velocity when the
kinetic energy of the system reaches zero.
potential energy of the system reaches zero.
mass returns to equilibrium.
restoring force reaches zero.

Answers

Answer: The mass has no velocity when kinetic energy=0.

Explanation: K=1/2mv^2 so if K=0, velocity must also equal 0.

5. A child wanting to make a cordial ice block, places 200g of cordial at 25°C in the freezer. If the freezer can remove energy at the rate of 250 joules per second, what time will it take for the cordial to freeze? (Assume the specific latent heat and specific heat capacity of cordial are the same as water.)​

Answers

The time taken for the cordial to freeze is 267.2 s.

What is the time taken for the cordial to freeze?

The amount of heat energy (Q) required to freeze the cordial can be calculated using the following formula:

Q = ml

where;

m is the massl is the latent heat of fusion of ice

Q = 334 J/g x 200 g

Q = 66,800 J

The time taken for the cordial to freeze is calculated as;

t = Q/W

where;

W is the rate of energy removal or powert is time

t = (66,800 J) / (250 J/s)

t = 267.2 s

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Two cars are moving with velocities 70 km/hr and west direction respectively.Find their relative velocity.​

Answers

Answer:

Explanation:

To find the relative velocity of two cars moving in different directions, we need to subtract their velocities. In this case, one car is moving with a velocity of 70 km/hr and the other car is moving with a velocity in the west direction.

Let's assume that the velocity of the second car is also 70 km/hr. Since the car is moving in the west direction, we can represent its velocity as -70 km/hr (negative sign indicates motion in the opposite direction).

Now, we can find the relative velocity of the second car with respect to the first car by subtracting the velocity of the first car from the velocity of the second car:

Relative velocity = Velocity of the second car - Velocity of the first car

= (-70 km/hr) - (70 km/hr)

= -140 km/hr

Therefore, the relative velocity of the second car with respect to the first car is -140 km/hr, which means that the two cars are moving away from each other at a speed of 140 km/hr.

PLS MARK ME BRAINLIEST

what are the two major types of mechanical energy and how do you calculate each equations with variables identified?

Answers

The two major types of mechanical energy are kinetic energy and potential energy.

The equation to calculate both of them are:

KE = 1/2 * m * v^2

PE = m * g * h

What is Kinetic energy?

Kinetic energy is described as the energy an object possesses due to its motion. The equation to calculate kinetic energy is:

KE = 1/2 * m * v^2

Where:

KE = Kinetic energy

m = Mass of the object

v = Velocity of the object

Potential energy is described as  the energy an object possesses due to its position or configuration.

. The equation to calculate gravitational potential energy is:

PE = m * g * h

Where:

PE = Gravitational potential energy

m = Mass of the object

g = Acceleration due to gravity (9.81 m/s^2 on Earth)

h = Height or elevation of the object relative to a reference point

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A 500 kg cannon fires a 10 kg cannon ball at 100 m/s. Assuming no force is stopping the cannon. What is the initial speed of the cannon ?

Answers

The initial speed of the cannon was 2 m/s.

The law of conservation of momentum states that the total momentum of a closed system remains constant if no external forces act on it. In this case, the cannon and the cannonball form a closed system, and no external forces are acting on it. Therefore, the total momentum of the system before and after the firing must be equal.


According to the law of conservation of momentum, the total momentum of the cannon and the cannonball must be conserved before and after the firing. Therefore, we can use the equation:

m(cannon) * v(cannon) = m(cannonball) * v(cannonball)

where m is the mass and v is the velocity.

Substituting the given values, we get:

500 kg * v(cannon) = 10 kg * 100 m/s

Solving for v(cannon), we get:

v(cannon) = 2 m/s

As a result, the cannon's starting speed was 2 m/s.

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Two objects, one with a mass of 75.0kg and the other with a mass of 60.0kg experience a gravitational force of attraction of 8.50x10-9N. How far apart are their
centers of mass?

Answers

Answer:

Approximately [tex]5.94\; {\rm N}[/tex].

Explanation:

The gravitational force between two objects of uniform mass is:

[tex]\displaystyle F = \frac{k\, M\, m}{r^{2}}[/tex],

Where:

[tex]k \approx 6.67 \times 10^{-11}\; {\rm m^{3}\, kg^{-1}\, s^{-2} }[/tex] is the gravitational constant,[tex]M[/tex] and [tex]m[/tex] are the mass of the two objects, and[tex]r[/tex] is the distance between the center of mass of the two objects.

Rearrange this equation to find [tex]r[/tex]:

[tex]\begin{aligned} r &= \sqrt{\frac{k\, M\, m}{F}} \\ &= \sqrt{\frac{(6.67 \times 10^{-11})\, (75.0)\, (60.0)}{8.50 \times 10^{-9}}}\; {\rm kg} \\ &\approx 5.94\; {\rm kg}\end{aligned}[/tex].

what are the disadvantages of moving with the speed of light or even faster​

Answers

For mass-containing things, it is impossible to move at or faster than the speed of light. Potential drawbacks include length contraction, time dilation, mass gain, gravitational effects, and high energy demands.

Why is travelling at the speed of light problematic?

If an object could ever move at the speed of light, its mass would become infinite. The required energy would therefore have to be infinite, which is not possible.

What are the drawbacks of speed?

The risk to other road users increases as you drive faster. Overspeeding cars put pedestrians in a very dangerous situation. Driving too quickly uses more fuel. After the speed reached a certain point, fuel usage skyrocketed.

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the laboratory for a body. I in rth. Total:[4] (2) bout a point? ...[1] hat are they? [2] le which is ntally by an (11 iform metre rule Figure 4.1 below shows astone of mass 2kg which drops from the top of a cliff and takes two seconds to strike the ground Acceleration of free fall.g=10m/s². Stone T 77 Figure 4.1 (a) Name the form of energy possessed by the stone before it falls. (b) Determine the height of the cliff (c) Calculate (i) Ground Height,h.......... [2] The kinetic energy of the stone when half way down. [1] Kinetic energy......... The final velocity of the stone as it strikes the [2] stone Klif​

Answers

The stone possesses potential energy at the top of the cliff, which is converted to kinetic energy as it falls toward the ground. Using the formula for the distance traveled by a freely falling object, we can calculate that the height of the cliff is 20 meters. The ground height is equal to zero, and when the stone is halfway down, it has a kinetic energy of 100 Joules. Using the formula for the final velocity of a freely falling object, we can calculate that the stone's final velocity as it strikes the ground is 20 m/s.

(a) The form of energy possessed by the stone before it falls is potential energy. When the stone is at the top of the cliff, it has the potential to do work due to its position relative to the ground. This potential energy is converted into kinetic energy as the stone falls towards the ground.

(b) We can use the formula for the distance traveled by a freely falling object to determine the height of the cliff:

d = 1/2 * g * t^2

where d is the distance, g is the acceleration due to gravity, and t is the time taken to fall.

Substituting the given values, we get:

d = 1/2 * 10m/s^2 * (2s)^2

d = 20 meters

Therefore, the height of the cliff is 20 meters.

(c)

(i) The ground height h is equal to zero since it is the reference level.

(ii) When the stone is halfway down, it has fallen a distance of d/2 = 10 meters. At this point, all of the potential energy has been converted to kinetic energy. We can use the formula for kinetic energy to calculate the kinetic energy of the stone:

KE = 1/2 * m * v^2

where KE is the kinetic energy, m is the mass of the stone, and v is its velocity.

Substituting the given values, we get:

KE = 1/2 * 2kg * (2 * g * d/2)

KE = 100 Joules

Therefore, the kinetic energy of the stone when halfway down is 100 Joules.

(iii) To find the final velocity of the stone as it strikes the ground, we can use the formula for the final velocity of a freely falling object:

v = sqrt(2 * g * d)

where v is the final velocity, g is the acceleration due to gravity, and d is the distance fallen.

Substituting the given values, we get:

v = sqrt(2 * 10m/s^2 * 20m)

v = sqrt(400)

v = 20 m/s

Therefore, the final velocity of the stone as it strikes the ground is 20 m/s.

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You decide to use your body as a Carnot heat engine. The operating gas is in a tube with one end in your mouth (where the temperature is 37.0 ∘C) and the other end at the surface of your skin, at 30.0 ∘C.
How much heat input is needed to accomplish the lift?

Answers

The question is incomplete, I think the question is:

You decide to use your body as a Carnot heat engine. The operating gas is in a tube with one end in your mouth (where the temperature is 37.0 ∘C) and the other end at the surface of your skin, at 30.0 ∘C.(a) What is the maximum efficiency of such a heat engine? Would it be a very useful engine? (b) Suppose you want to use this human engine to lift a 2.50kg box from the floor to a tabletop 1.20m above the floor. How much must you increase the gravitational potential energy, and how much heat input is needed to accomplish this? (c) How many 350-calorie (those are food calories, remember) candy bars must you eat to lift the box in this way? Recall that 80% of the food energy goes into heat.

We need to input about 1278 J of heat into the heat engine to lift the box, and we need to eat about 1.09 candy bars to lift the box

The Carnot heat engine is an idealized thermodynamic cycle that operates between two heat reservoirs and achieves the maximum possible efficiency. It is a theoretical model used to study the behavior of real-world heat engines and provides a benchmark for their performance.

a) The maximum efficiency of a Carnot heat engine is given by the equation:

η = 1 - Tc/Th

where η is the efficiency, Tc is the temperature of the cold reservoir (in this case, 30.0 °C), and Th is the temperature of the hot reservoir (in this case, 37.0 °C).

Plugging in the numbers, we get:

η = 1 - 303 K/310 K ≈ 0.023 or 2.3%

This is a very low efficiency, and the heat engine would not be very useful for doing work.

b) To lift a 2.50 kg box from the floor to a tabletop 1.20 m above the floor, we need to increase its gravitational potential energy by:

ΔPE = mgh

where m is the mass of the box, g is the acceleration due to gravity (9.81 m/s^2), and h is the height the box is lifted.

Plugging in the numbers, we get:

ΔPE = (2.50 kg)(9.81 m/s^2)(1.20 m) ≈ 29.4 J

To accomplish this, we need to input heat Q into the heat engine. Since the efficiency of the heat engine is only 2.3%, the amount of heat needed is:

Q = ΔPE/η = (29.4 J)/(0.023) ≈ 1278 J

So we need to input about 1278 J of heat into the heat engine to lift the box.

c) To input 1278 J of heat into the heat engine, we need to consume food with a total energy content of:

E = Q/ηfood

where ηfood is the efficiency of converting food energy into heat energy. Since 80% of the food energy goes into heat, we have:

ηfood = 0.80

Plugging in the numbers, we get:

E = (1278 J)/(0.80) ≈ 1598 J

To convert this energy content into calories, we divide by 4.184 J/cal, giving:

E = 381 cal

Finally, to determine the number of 350 calorie candy bars needed, we divide the total energy content by the energy content per candy bar:

N = E/Ebar

where Ebar is the energy content of a single candy bar (350 cal). Plugging in the numbers, we get:

N = (381 cal)/(350 cal/bar) ≈ 1.09 bars

So we need to eat about 1.09 candy bars to lift the box.

Therefore, To lift the box, we must put approximately 1278 J of heat into the heat engine and consume approximately 1.09 candy bars.

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what is gravitatinal force ?​

Answers

An attractive force that acts between any two objects

Answer: The force of gravity, or gravitational force, pulls objects with mass toward each other.

We often think about the force of gravity from Earth. This force is what keeps your body on the ground.

But any object with mass exerts a gravitational force on all other objects with mass. For example, there is a gravitational force between you and every object around you.

The gravitational force between two objects is larger when the masses of the objects are larger. That’s why you can feel the gravitational force between you and Earth, but the force between you and objects with smaller masses is too weak to feel.

The gravitational force between two objects also depends on the distance between their centers. The further objects are from one another, the weaker the force is.

Two children setup a “telephone” by placing a long, slender aluminum (Y = 6.9 × 1010 N/m2) rod that has a length of 6.1-m between their two houses. To communicate, a child taps a coded message on one end. How long do the sound waves take to reach the other end? Note: the density of aluminum is 2700 kg/m3.

Answers

The time takes  is 1.19 ms for the sound waves to travel the length of the aluminum rod between the two houses.

The speed of sound in aluminum can be determined utilizing the condition

v = sqrt(Y/ρ),

where Y is the Youthful's modulus and ρ is the thickness of the material. Connecting the qualities for aluminum, we get

v = [tex]sqrt(6.9x10^10 N/m^2/2700 kg/m^3) = 5110 m/s[/tex].

The time it takes for the sound waves to venture to every part of the length of the aluminum pole can be determined utilizing the condition

t = d/v,

where d is the distance and v is the speed of sound. Connecting the qualities, we get

t = 6.1 m/5110 m/s = 0.00119 s or 1.19 ms.

Subsequently, it takes 1.19 ms for the sound waves to venture to every part of the length of the aluminum bar between the two houses.

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Price $15 12 9 6 3 Quantity Demanded per Month 1 2 3 5 7 Price $15 12 9 6 3 In the BOX what you would expect to see if you plotted the numbers on the graph. The quantit demand pe month dec 0 1 2 3 4 5 6 7 Quantity b. It costs Charlene $2.00 to ride to bus to the dog owners house each time she goes. What number of dog walks will give her the most profit?​

Answers

From the table, we can see that Charlene will have the most profit ($21) when she walks 3 dogs per month, charging $9 per walk.

How to solve

Based on the provided data, we can create a demand schedule for the prices and the quantity demanded per month.

Let's first organize the data in a table:

Price ($) Quantity Demanded per Month

15 1

12 2

9 3

6 5

3 7

If you plotted these numbers on a graph, you would expect to see a downward-sloping curve, illustrating the inverse relationship between price and quantity demanded. As the price decreases, the quantity demanded per month increases.

Now let's consider Charlene's costs and profits from walking dogs. It costs her $2.00 for each bus ride to the dog owner's house.

To calculate her profit, we need to find her total revenue at each price point, then subtract her total costs.

Price ($) Quantity Demanded per Month Total Revenue ($) Total Costs ($) Profit ($)

15 1 15 2 13

12 2 24 4 20

9 3 27 6 21

6 5 30 10 20

3 7 21 14 7

From the table, we can see that Charlene will have the most profit ($21) when she walks 3 dogs per month, charging $9 per walk.

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The boy biked 600 m at a speed of 10 m/s, how long did it take him to bike the total distance?

Answers

Answer:60 seconds

Explanation: Since we have the boy's initial location si (0m), final location sf (600m) and his velocity v, we can have our position equation like so:

sf = si + vt
600 = 0 + 10t

Solve for t by dividing 600 by 10 and your time t = 60s

What is the magnitude of the force in coulomb's law when one of the charge is double

Answers

Answer: Doubled

Explanation:

Use the heating curve (Figure 1) to answer the question.
Temperature (°C)
200
150
100
50
0
-50
-100
-150
200 400 600 800 1000 1200
Energy (J)
What is the boiling point of the substance represented?
0
-100 °C
150 °C
-50 °C
50 °C

Answers

Answer:

Melting Point = -50 °C

Boiling Point = 50 °C

Explanation:

A heating curve displays a substance in its 3 states.

On the graph, each region where the slope is positive represents the substance as a solid, liquid, or gas.

When the slope is 0, this is the temperature point at which the substance's state of matter has changed (i.e., melting or boiling/vaporization point) – also known as a phase transition. Essentially, the 0 slope regions are where the substance is changing from one state of matter to the next.

(When the substance is being heated, it's absorbing energy, but when it reaches a phase transition point, the substance begins to consume energy to change its matter state. That's why the temperature doesn't go up while the substance's internal Energy increases.)

In (Figure 1), where 'x' is Energy (J) and 'y' is Temperature (°C):

Region A (0 J ≤ x ≤ 200 J):

The slope is positive, so the substance is in a constant matter state. Because it's the first sloped region, the substance is in its solid state from -100 °C to -50 °C.

Region B (200 J ≤ x 600 J):

The slope is 0, so the substance has reached a phase transition point. Because the previous region was when the substance was solid, that means that the temperature throughout Region B is the melting point at -50 °C.

Region C (600 J ≤ x ≤ 800 J):

The slope is positive so the substance is in a constant matter state. We've already identified when the substance was solid and when it melted, so now the substance is in its liquid state from -50 °C to 50 °C.

Region D (800 J ≤ x ≤ 900 J):

The slope is 0, and since the previous region was when the substance was a liquid, it's now reached its boiling point at 50 °C.

Region E (900 J ≤ x ≤ 1000 J):

The slope is positive, and we've previously identified all of the transition points and matter states except for one, so the substance is now in its gaseous state after reaching 100°C.

(Once a substance reaches its gaseous state, the Temperature/Energy ratio is constant.)

As the pendulum swings from position A to position B, what is the relationship of kinetic energy to potential energy (neglect friction)? (5 points)


The kinetic energy increase is equal to the potential energy decrease.

The potential energy increase is equal to the kinetic energy decrease.

The kinetic energy and potential energy remain the same.

The kinetic energy increase is more than the potential energy decrease.

Answers

As the pendulum swings from position A to position B, the potential energy decreases while the kinetic energy increases. According to the law of conservation of energy, the total energy in a system remains constant, neglecting friction. Therefore, the potential energy lost by the pendulum is converted into kinetic energy. The correct relationship of kinetic energy to potential energy as the pendulum swings from position A to position B is:

The potential energy decrease is equal to the kinetic energy increase.

So, the answer is option B.

Answer:

The potential energy increase is equal to the kinetic energy decrease.

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