Answer:
E = F * S definition of energy
P = E / t = F * S / t definition of power
P = 5.6E4 N * 4.5 m / 4.2 s = 60,000 watts
a defender running away from a goalkeeper at 5m/s is hit in the back by the goal kick. the ball stops dead and the players speed increases to 5.5m/s if the ball had a mass of 500g and the player mass is 70k how fast was the ball moving?
The goal kick strikes a defender racing at 5 m/s away from a goalkeeper in the back. The ball was moving at a speed of 70 m/s if it weighed 500g and the player's mass was 70k.
Why does the goalie in a football game pull his hands back after holding the ball that has been shot towards the goal?The goalkeeper extends the amount of time he has to hold the ball by pulling his hands back. He lessens the force (rate of change of momentum) the football exerts on him by lengthening the time.
Write the formula for momentum and define it.A vector quantity, momentum. A body's momentum is equal to P=m.v if it is travelling at a speed of v while having mass m. P=mv describes the magnitude of the momentum. Because momentum is a function of mass and velocity, its unit is the product of those two quantities.
By using conservation of momentum,
Initial momentum = Final momentum
(5 x 70) + (v x 0.5) = (5.5 x 70) + (0 x 0.5)
350 + 0.5v = 385 + 0
0.5v = 35
v = 70 m/s
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Answer the following. (a) What is the surface temperature of Betelgeuse, a red giant star in the constellation of Orion, which radiates with a peak wavelength of about 970 nm? K (b) Rigel, a bluish-white star in Orion, radiates with a peak wavelength of 145 nm. Find the temperature of Rigel's surface. K
Answer:
(a) T = 2987.6 k
(b) T = 19986.2 k
Explanation:
The temperature of a star in terms of peak wavelength can be given by Wein's Displacement Law, which is as follows:
[tex]T = \frac{0.2898\ x\ 10^{-2}\ m.k}{\lambda_{max}}[/tex]
where,
T = Radiated surface temperature
[tex]\lambda_{max}[/tex] = peak wavelength
(a)
here,
[tex]\lambda_{max}[/tex] = 970 nm = 9.7 x 10⁻⁷ m
Therefore,
[tex]T = \frac{0.2898\ x\ 10^{-2}\ m.k}{9.7\ x\ 10^{-7}\ m}[/tex]
T = 2987.6 k
(b)
here,
[tex]\lambda_{max}[/tex] = 145 nm = 1.45 x 10⁻⁷ m
Therefore,
[tex]T = \frac{0.2898\ x\ 10^{-2}\ m.k}{1.45\ x\ 10^{-7}\ m}[/tex]
T = 19986.2 k
A satellite of mass m is orbiting Earth in a stable circular orbit of radius R. The mass and radius of Earth are ME and RE , respectively. Express your answers to parts (a), (b), and (c) the following in terms of m, R, ME , RE , and physical constants, as appropriate.
a. Derive an expression for the speed of the satellite in its orbit.
b. Derive an expression for the total mechanical energy of the satellite-Earth system in its orbit.
c. Derive an expression for the period of the satellite’s orbit.
Answer:
a) v = [tex]\sqrt{G \frac{M_e}{(R+R_e)} }[/tex], b) Em = - ½ m [tex]G \frac{M_e}{(R+R_e)}[/tex], c) T = 2π [tex]\sqrt{\frac{ (R+R_e)^3 }{G M_e } }[/tex]
Explanation:
a) For this exercise we must use Newton's second law with the gravitational force
F = ma
[tex]G \frac{m M_e}{(R+R_e)^2 }[/tex] = m a
the acceleration of the satellite is centripetal
a = [tex]\frac{v^2}{(R+R_e)}[/tex]
we substitute
[tex]G \frac{m M_e}{(R+R_e)^2 } = m \frac{v^2}{ (R+R_e)}[/tex]
[tex]G \frac{M_e}{(R+R_e)}[/tex] = v²
v = [tex]\sqrt{G \frac{M_e}{(R+R_e)} }[/tex]
the distance is from the center of the earth
b) mechanical energy is the sum of kinetic energy plus potential energy
Em = K + U
Em = ½ m v² - G m M / (R + R_e)
we substitute the expression for the velocity
Em = ½ m [tex]G \frac{M_e}{(R+R_e)}[/tex] - [tex]G \frac{M_e}{(R+R_e)}[/tex]
Em = - ½ m [tex]G \frac{M_e}{(R+R_e)}[/tex]
c) as the orbit is circulating, the velocity modulus is constant
v = d / t
in a complete orbit the distance traveled of the circle is
d = 2π (R + R_e)
where time is called period
v = 2π (R + R_e)
T = 2π (R + R_e) / v
we substitute the speed value
T = 2π (R + R_e) [tex]\sqrt{\frac{(R+R_e) }{G M_e } }[/tex]
T = 2π [tex]\sqrt{\frac{ (R+R_e)^3 }{G M_e } }[/tex]
(a) An expression for the speed of the satellite in its orbit.
[tex]V=\sqrt{G\dfrac{M_e}{R+R_e}[/tex]
(b) An expression for the total mechanical energy of the satellite-Earth system in its orbit.
[tex]E_m =\dfrac{1}{2}mG\dfrac{M_e}{(R+R_e)}[/tex]
(c) An expression for the period of the satellite’s orbit.
[tex]T=2\pi\sqrt\dfrac{(R+R_e)^3}{GM_e}[/tex]
What are satellites?A satellite is a moon, planet or machine that orbits a planet or star. For example, Earth is a satellite because it orbits the sun
a) For this exercise we must use Newton's second law with the gravitational force
F = ma
[tex]ma =G\sqrt{\dfrac{mM_e}{(R+R_e)}[/tex]
the acceleration of the satellite is centripetal
[tex]a=\dfrac{v^2}{R+R_e}[/tex]
we substitute
[tex]G\dfrac{mM_e}{(R+R_e)}=m\dfrac{v^2}{(R+R_e)}[/tex]
[tex]G\dfrac{M_e}{(R+R_e)}=v^2[/tex]
[tex]v=\sqrt{G\dfrac{M_e}{(R+R_e)}[/tex]
b) mechanical energy is the sum of kinetic energy plus potential energy
Em = K + U
[tex]Em =\dfrac{1}{2}m v^2 - \dfrac{G m M} {(R + R_e)}[/tex]
we substitute the expression for the velocity
[tex]E_m=\dfrac{1}{2}mG\dfrac{M_e}{(R+R_e)}-G\dfrac{M_e}{(R+R_e)}[/tex]
[tex]E_m=-\dfrac{1}{2}G\dfrac{M_e}{(R+R_e)}[/tex]
c) as the orbit is circulating, the velocity modulus is constant
[tex]v=\dfrac{d}{t}[/tex]
in a complete orbit the distance traveled of the circle is
[tex]d = 2\pi (R + R_e)[/tex]
where time is called period
[tex]v = 2\pi (R + R_e)[/tex]
[tex]T = \dfrac{2\pi (R + R_e)} { v}[/tex]
we substitute the speed value
[tex]T = 2\pi (R + R_e) . \sqrt{\dfrac{(R+R_e)}{GM_e}[/tex]
[tex]T=2\pi\sqrt{\dfrac{(R+R_e)}{GM_e}[/tex]
(a) An expression for the speed of the satellite in its orbit.
[tex]V=\sqrt{G\dfrac{M_e}{R+R_e}[/tex]
(b) An expression for the total mechanical energy of the satellite-Earth system in its orbit.
[tex]E_m =\dfrac{1}{2}mG\dfrac{M_e}{(R+R_e)}[/tex]
(c) An expression for the period of the satellite’s orbit.
[tex]T=2\pi\sqrt\dfrac{(R+R_e)^3}{GM_e}[/tex]
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Kind of energy a piece of radioactive metal contains
Answer:
Radioactive materials give off a form of energy called ionizing radiation.
Some bat species have auditory systems that work best over a narrow range of frequencies. To account for this, the bats adjust the sound frequencies they emit so that the returning, Doppler-shifted sound pulse is in the correct frequency range. As a bat increases its forward speed, should it increase or decrease the frequency of the emitted pulses to compensate?
Answer:
As a bat increases its forward speed, it should decrease the frequency of the emitted pulses to compensate.
decrease
Explanation:
Decreasing the frequency of the emitted pulse will help the bat reduce its frequency caused by its forward motion. The forward motion shifts the bat's auditory frequency to a higher frequency; consequently, the bat should adjust downwards the frequency of the emitted pulse so the reflected pulse will be in the correct frequency range.
A 25 kg box of roofing shingles is lifted 15 meters vertically to the top of a roof. How much work is done on the box?
Important Formulas:
[tex]F=ma[/tex]
force(measured in newtons) = mass(measured in kg) * acceleration(measured in m/s^2)
[tex]w=Fd[/tex]
work(measured in joules) = force(measured in newtons) * distance(measured in meters)
__________________________________________________________
Given:
[tex]m=25kg[/tex]
[tex]d=15m[/tex]
[tex]w=?[/tex]
We know that the acceleration due to gravity is 9.8 m/s^2.
__________________________________________________________
Finding force:
[tex]F=ma[/tex]
[tex]F=25\times9.8[/tex]
[tex]F=245N[/tex]
__________________________________________________________
Finding work:
[tex]w=Fd[/tex]
[tex]w=245\times15[/tex]
__________________________________________________________
[tex]\fbox{w = 3675 Joules}[/tex]
A boat has a speed of 20m/s in still waters. what is the speed in a river flowing due east with a velocity of 5m/s if the boat is heading north. How far from a point directly north on the other side of the river will the boat arrive if the width of the river is 10m.
The boat will arrive 2.5 meter in east far from a point directly north on the other side of the river.
What is velocity?The rate at which a body's displacement changes in relation to time is known as its velocity. Velocity is a vector quantity with both magnitude and direction.
A boat has a speed of 20m/s in still waters.
The velocity of river is 5m/s in east.
The width of the river is = 10 meter.
Hence, time taken by the board to cross the river = 10/20 second
= 0.5 second.
In this time, the board will move in east direction = 5×0.5 meter = 2.5 meter.
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QUESTION 4
A student lifts a 400 N sandbag 2 meters off the ground. How much work, in joules, did the student perform?
Answer:
800J
Explanation:
W = Fs, Work equals force times displacement
in this case, the force is 400N and the displacement is 2 meters.
The regular SI unit for work is joules
In each of the four situations below an object is experiencing (nearly) uniform circular motion. State what force is providing the centripetal force required to keep the object moving in a circle: a. A car driving around a track. b. A ball being swung on the end of a string. c. The moon orbiting the earth. d. A rotating wheel.
Answer:
Explanation:
Given that a centripetal force is a form of force that gives rise or causes a body to move in a curved path.
Hence;
1. When a car is being driven around a track, it is the FORCE OF FRICTION that is acting upon the turned wheels of the vehicle, which transforms into the centripetal force required for circular motion.
2. When a ball being is swung on the end of a string, TENSION FORCE acts upon the ball, which transforms the centripetal force required for circular motion.
3. When the moon is orbiting the earth, it is the FORCE OF GRAVITY acting upon the moon, which transforms the centripetal force required for circular motion.
4. A rotating wheel on the other hand has NO centripetal force because centripetal force is pull towards the center of a motion. However the speed of the object is tangent to the circle, while the direction of the force is also perpendicular to the direction of the rotating wheel.
The force that provides the centripetal force in each of the given situations are;
A) Friction Force
A) Friction ForceB) Tension Force
A) Friction ForceB) Tension ForceC) Force of gravity
A) Friction ForceB) Tension ForceC) Force of gravity D) No centripetal force
When an object is in circular motion, the force that keeps it moving round the circle while centrifugal force is the one that tries to pull the object away from the center.
A) When a car is driving around a track, there is a frictional force between the tires of the car and the track that acts on the vehicle to keep it in that circular motion. This frictional force is the centripetal force required to keep the vehicle in circular motion.
B) When a ball is swing on the end of a string, there is an upward force called tension force that acts on the ball to keep it swinging in circular motion. Thus, the centripetal force here is provided by the tension force.
C) When the moon is orbiting the earth, there is a force of gravity exerted by the earth on the moon that keeps the moon in a circular motion about Earth instead of moving in a straight line.
D) For a rotating wheel, the centripetal force does not do any work. The reason for that is because the centripetal force points toward the center of the circle, and as a result it means that the velocity of the rotating wheel is tangent to the circle.
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with what speed will a clock have to be moving in order to run at a rest that is one half the rate of clock at rest
The speed at which a clock would have to be moving in order to run at half the rate of a clock at rest depends on the theory of relativity that you are using.
What is the clock speed about?In special relativity, time dilation is the phenomenon where time appears to pass differently for objects in motion relative to an observer at rest.
According to the theory, time appears to slow down for an object as it approaches the speed of light. The rate at which time appears to pass for an object is given by the equation:
T' = T / [tex]\sqrt{(1 - (v^2 / c^2))}[/tex]
Where T is the time as measured by an observer at rest, T' is the time as measured by an observer moving relative to the object, v is the velocity of the object, and c is the speed of light.
In addition, this is a theoretical scenario, practically in order to measure time dilation in a laboratory, it is required a very high precision of measurements, that are currently not possible.
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A bullet traveling at 5.0 x10^2 meters per is brought to rest by an impulse of 50 Newton*seconds. Find the mass of the bullet.
The bullet stops moving on hitting on a surface. Hence, the impulse here is equal to the momentum. Therefore, the mass of the bullet is 0.1 Kg.
What is impulse?Impulse in physics is the change in momentum. It is the product of the force and change in time.
hence, impulse = f. dt
When the bullet is travelling with a velocity of 500 m/s it has a momentum. When it brought to rest, momentum become zero. Thus, the momentum is equal to the impulse here.
Therefore, f.dt = m. v
f.dt = 50 N s
v = 500 m/s
m = 50 N s/500 m/s = 0.1 Kg
Therefore, the mass of the bullet is 0.1 Kg.
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A supercluster is 100 million light-years across. How long would it take light to travel from one edge of the supercluster to the center of the supercluster?
Answer:
50 million years
Explanation:
light years is the distance light travels in one year given that the supercluster is 100 million light years across the the distance to the center will be half that amount therefore the answer is 50 million years
Please give me the answer to this question
There is not enough information to determine the work done. Option iv
What is the work done?Let us note that we say that there is work done when the force that has been applied moves a distance in the direction of the force. In this case, we have been told that there is the combination of the works that is done by the object.
Now, we also have to note that we do not have other information to determine the work done such as the magnetic feild and the mass of the electron. All these are lacking in the question.
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HELPPP PLEASEEEEE, BRIANLEST WILL BE GIVEN ON CORRECT!
Answer:
a. 6000J or 6KJ
b. Force =600
just give me the right answer!
If the distance between two objects decreased, what would happen to the force of gravity between them?
It would increase.
It would stay the same.
It would depend on the speed.
It would decrease.
It would increase................
Please help me thank you
The gravitational potential energy of a body is determined by the equation U=mgh, where m is the body's mass, g is its gravitational force, and h is its height. The relationship between mechanical energy and gravitational potential energy is described by the equation E=U+K.
What is the kinetic energy equation?KE= 1/2 m v2
The relationship between kinetic energy and an object's mass and square of its velocity is direct: K.E. = 1/2 m v2.
We compute kinetic energy because...It provides information on how a substance's mass impacts its velocities. Take this as a case study. A lorry and a sleek vehicle powered by the same engine cannot go at the same pace because to their different designs.
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three way to calculate average are
What are the differences between thermionic and photoelectric emission?
Answer:
During thermionic emission, electrons are emitted from metal surfaces by providing heat energy, while during photoelectric emission, light energy is emitted when electrons are emitted from the surface of metal
Hope it helps :)
Two students are balancing on a 10m seesaw. The seesaw is designed so that each side of the seesaw is 5m long. The student on the left weighs 60kg and is sitting three meters away from the fulcrum at the center. The student on the right weighs 45kg. The seesaw is parallel to the ground. The mass of the board is evenly distributed so that its center of mass is over the fulcrum. What distance from the center should the student on the right be if they want the seesaw to stay parallel to the ground?
a. 4m
b. 5m
c. 2m
d. 3m
Answer:
Option A. 4 m
Explanation:
Please see attached photo for diagram.
In the attached photo, X is the distance from the centre to which the student on the right must sit in order to balance the seesaw.
Clockwise moment = X × 45
Anticlock wise moment = 3 × 60
Clockwise moment = Anticlock wise moment
X × 45 = 3 × 60
X × 45 = 180
Divide both side by 45
X = 180 / 45
X = 4 m
Thus, the student must sit at 4 m from the centre.
The distance from the center the student on the right will be if they want the
seesaw to stay parallel to the ground is 4m
The question tells us that X is the distance to the center , each side of the
see saw is 5m with total length being 10m. This is explained in the
attached picture.
Clockwise moment = X × 45
Anticlock wise moment = 3 × 60
Clockwise moment = Anticlock wise moment
X × 45 = 3 × 60
X × 45 = 180
= 180 / 45
= 4m
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An 80-kg man balances the boy on a teeter-totter as shown. What is the approximate mass of the boy? What, approximately, is the magnitude of the downward force exerted on the fulcrum? Ignore the weight of the board.
I know the first answer is 20 kg and the second answer is 1000N. Have no idea how to get these answers though. Please help? Will rate!!
The boy weighs at about 80 kg. When, as illustrated, a N 784 guy balances the youngster on a teeter-totter.
What is ideal interpretation of mass?A way to determine how much material, in mass, makes up a physical body.
In classical mechanics, an object's mass is essential to Newton's equations of motion because it affects the force required to accelerate it and, subsequently, how much inertia it has.
Language expert Peter Trudgill claims that the name "Tittermatorter" from the Norfolk language is its origin. Trudgill can trace all of his great-great-grandparents to a tiny region of eastern Norfolk.
As per the question:
Weight is come under gravity and become force
80g = mg
m = 80
Force = 80(9.8) = 784N
Thus, the answer is 784N.
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Electromagnetic waves are commonly referred to as _________
O electricity
O magnetism
O light
What are the magnitude and direction of the current in the 20 Ω resistor in (Figure 1)?
Express your answer with the appropriate units. Enter positive value if the current is clockwise and negative value if the current is counterclockwise.
To solve this we must be knowing each and every concept related to net current. Therefore, the circuit's overall net current is 0.1 A, flowing clockwise.
What is the net current?The term "net current" refers to the total currents after taking current direction into account. If a node sends 1 mA inside and 5 mA out, the total current equals 4 mA out.
The sum of all entering currents must match the sum of all exiting currents, according to KCL. According to Ohm's Law, the current flowing is equivalent to the combined voltage dividing by the entire resistance. In contrast to a series circuit, where the total current is the same across all of the components, the total current inside a parallel connection is really only equal to the particular current in that part of the circuit.
Net current
i = V / Ri
= (9 - 6) / (10 + 20)i
= 0.1 A
in clockwise way
Therefore, the circuit's overall net current is 0.1 A, flowing clockwise.
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1. Three confused sled dogs are trying to pull a sled across the Alaskan snow. Tim pulls east with a force of 42 N; Sam also pulls east, but with a force of 53 N; and big Ethan pulls west with a force of 67 N. What is the net force on the sled? then find the acceleration?
2. A 944-kg dragster, starting from rest, attains a speed of 31,2 m/s in 0.670 s. a. Find the average acceleration of the dragster.
b. What is the magnitude of the average net force on the dragster during this time?
c. What horizontal force does the seat exert on the driver if the driver has a mass of 68.0 kg?
Please try to atleast answer one
Answer:
Explanation:
According to the statement, three confused sleigh dogs are trying to pull a sled across the Alaskan snow.
Forces in same direction gets added , so 35N + 42N=77N and the Net Force is 77N -53N as it is acting in opposite direction.
Net force is 25N in east to the maximum without any hassle.
-------------------------------------------------------------------------------------------------
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Why is Energy, Work and Power all Scalar Quantity?
Answer:
Explanation:
We already know that Force is a vector. Weight being a force, is also a vector quantity. Displacement is distance in a specific direction, hence it is a vector quantity too. ... since energy, work done and time are scalar, Power is a scalar quantity
A 6 kg bowling ball is lifted 1.2 m into a storage rack. The acceleration of gravity is 9.8 m/s². Calculate the increase in the ball's potential energy. Answer in units of J.
Answer:
70.56 J
Explanation:
The increase in potential energy of the ball can be calculated using the formula:
PE = mgh
where:
PE is the increase in potential energy
m is the mass of the ball (6 kg)
g is the acceleration of gravity (9.8 m/s²)
h is the height the ball is lifted (1.2 m)
Substituting in the values, we get:
PE = (6 kg)(9.8 m/s²)(1.2 m)
This simplifies to:
PE = 70.56 J
So the increase in the ball's potential energy is 70.56 J.
What is the resulting acceleration when a net force of 18 N is applied to a 3.0 kg mass?
O A. 6.0 m/s2
C. 54 m/s2
O B. 15 m/s2
O D. 9.8 m/s2
Answer:
F =ma
a=f/m =18/3= 6m/m²
Explanation:
the resulting acceleration will 6 m/s² because the question asking us to solve for the acceleration.
3 ) find the electrical force between the two charges Q1=3mc ,Q2=-6mc when they are 0.3 m parted ?
find the amount of the force when Q1 is doubled ?
Answer:
F = 3.6 10⁶ N
Explanation:
The expression for the electric force is
F = [tex]k \ \frac{q_1 q_2}{r^2}[/tex]
in this case it indicates that the charge q1 is doubled
q₁ = 2 3 10⁻³ C
q₁ = 6 10⁻³ C
let's reduce the magnitudes to the SI system
q₂ = 6 10⁻³ C
r = 0.3 m
let's calculate
F = 9 10⁹ 6 10⁻³ 6 10⁻³ / 0.3²
F = 3.6 10⁶ N
HELPPP PLEASEEEEE, BRIANLEST WILL BE GIVEN ON CORRECT!
Answer:
a. 25000 J
b. 2500 J/s
Explanation:
Given,
Distance ( s ) = 50 m
Force ( f ) = 500 N
a.
To find : -
Work done ( W ) = ?
Formula : -
W = fs
W
= 500 x 50
= 25000 J
Therefore,
the work done by the force the horse exerts is
25000 J.
b.
To find : -
Power ( P ) = ?
Formula : -
W = Pt
P = W / t
P
= 25000 / 10
= 2500 J/s
Therefore,
the power produced if the movement took 10 s
is 2500 J/s.
Answer:
2500j/s
Explanation:
what energy transformation is preformed by a radio
Answer:
Chemical energy to sound energy to heat energy
You are riding your bicycle down the street at a speed of 14 m/s. Your bicycle frame has a mass of 6.6 kg, and each of its two wheels has mass 2.2 kg and radius 0.35 m. Each wheel can be thought of as a hollow hoop (assuming that the rim has much larger mass than the spokes). What is the total kinetic energy of the bicycle (in Joules), taking into account both the translational and rotational motion
Answer:
1078 Joules
Explanation:
The computation of the total kinetic energy of the bicycle is shown below:
Given that
mass of bicycle's frame (m) = 6.6 kg
mass of each wheel (M) = 2.2 kg
radius of each wheel (r) = 0.35 m
And, the linear speed (v) = 14 ms
Now
As we know that
Angular velocity (ω) = v ÷ r
= 140 ÷ .35
= 40 rads
Total kinetic energy = translational kinetic energy + rotational kinetic energy
= (1 ÷2 × m × v^2) + (2 × 1 ÷ 2×I × ω^2)
= (0.5 × 6.6 × [14]^2) + (M × r2 × ω^2)
= 646.8 + (2.2 × 0.35 × 0.35 × [40]^2)
= 646.8 + 431.2
= 1078 Joules