Answer:
The speed of the stream is 6 km/h and the speed of the swimmers in still water is 14 Km/h
Explanation:
Relative Speeds
When swimming downstream, the velocity (speed, really) of the stream (Vs) and the speed of the swimmers (Vm) are collaborative. When swimming upstream the speed of the stream subtracts to the speed of the swimmers, thus:
Vm + Vs = 20
Vm - Vs = 8
Adding both equations:
2Vm = 28
Vm = 28/2 = 14
From the first equation:
Vs = 20 - Vm = 20 - 14 = 6
The speed of the stream is 6 km/h and the speed of the swimmers in still water is 14 Km/h
I was walking down the street and collapsed. My heart was racing and I struggled with
breathing. As I lay there, I watched as people walked by me not offering to help. At
one point I thought a young lady was looking towards me but when she noticed
everyone else's behavior, she turned and walked on past me. This scenario shows:
O the mere exposure effect.
O the fundamental attribution error,
O social loafing.
the foot-in-the-door phenomenon.
O the bystander effect.
Answer:
O the bystander effect.
Explanation:
In psychology, bystander effect is a theory that explains the unwillingness of a person to render help due to the presence of others. This theory explains that there is every tendency to help a victim in need when others are not there but act contrarily in the presence of others.
This is the case in this question where someone collapsed and laid helplessly on the floor due to difficulty in breathing. People walked past this victim without rendering assistance, however, a young lady who was about to help also walked past when she noticed that others were there and not offering help. This young lady has just portrayed the "BYSTANDER EFFECT".
20 pts !!!!
Four identical pallets of bricks, each with a mass of 40 kg with a square cross-sectional area of 0.50 m2, are stacked on the floor. What is the change in height of the pallet at the bottom of the stack if the pallets are 5.0 m tall when not stacked?
a.
1.04 μm
b
0.78 μm
c
0.26 μm
d
0.16 μm
why does a typhoon hit a location twice?
A star has ______________________________________________; it appears to be moving across the sky as a night progresses.
Answer:
Apparent Motion
Explanation:
Apparent Motion of a star is a scientific term that describes the phenomenon that is observed as a result of the earth's rotation which is based on the area or where the observer is situated, and then the point at which the star is found comparable to the rotation axis of the earth.
This often makes the start to appear like it's moving across the sky.
Hence, A star has APPARENT MOTION; it appears to be moving across the sky as the night progresses.
What biotic factors do the organisms in Movile Cave rely on?
Answer:
All cave animals and organisms fit into three categories. Placement into these categories depends on how much time the organisms actually spend in the cave.
The first type is known as Trogloxenes. You can think of trogloxenes as cave visitors. They come and go at will, but use the cave for specific parts of their life cycle (hibernation, giving birth, etc.) Although it spends specific parts of its life in the cave, it will never spend a complete life cycle in the cave. Examples of animals that are All cave animals and organisms fit into three categories. Placement into these categories depends on how much time the organisms actually spend in the cave.
The first type is known as Trogloxenes. You can think of trogloxenes as cave visitors. They come and go at will, but use the cave for specific parts of their life cycle (hibernation, giving birth, etc.) Although it spends specific parts of its life in the cave, it will never spend a complete life cycle in the cave. Examples of animals that are trogloxenes are:
-Bats
-Bears
-Skunks
-Raccoon
-Moths (sometimes)
Troglophiles are the next level. These are organisms that survive outside the cave, but may prefer to live outside of it. They leave the cave only in search for food. A troglophiles can chose to live its entire life either inside or outside of a cave. Some examples of trogphiles are:
-Beetles
-Worms
-Frogs
-Salamanders
-Crickets
-Spiders
-Crayfish (sometimes)
Troglobites are animals that live in the cave but do not come out. They often have physical adaptions to the cave life like no vision, or loss pigment because light does not reach this part of the cave. Examples would be
-Snails that have thin white shells and small eyes
-Blind cave fish which has no eyes and no color
-Kauai Cave Wolf Spider which also has no eyes.
Bats are not true troglobites because they only use the cave for sleep, hiding and reproduction. There is about 50 000 troglobites in the world. are:
-Bats
-Bears
-Skunks
-Raccoon
-Moths (sometimes)
Troglophiles are the next level. These are organisms that survive outside the cave, but may prefer to live outside of it. They leave the cave only in the search for food. A troglophiles can chose to live its entire life either inside or outside of a cave. Some examples of trogphiles are:
-Beetles
-Worms
-Frogs
-Salamanders
-Crickets
-Spiders
-Crayfish (sometimes)
Troglobites are animals that live in the cave but do not come out. They often have physical adaptions to the cave life like no vision, or loss of pigment because light does not reach this part of the cave. Examples would be
-Snails that have thin white shells and small eyes
-Blind cavefish which has no eyes and no color
-Kauai Cave Wolf Spider which also has no eyes.
Bats are not true troglobites because they only use the cave for sleep, hiding, and reproduction. There are about 50 000 troglobites in the world.
Draw a ray diagram to show the formation of an image when the object is placed beyond the ‘c’of a concave mirror.
the object is real inverted and diminishes
What is the net work done to lift a 6 kg block a height of 5.3 meters and then lower it back to the ground where it started?
Answer:
636 J
Explanation:
The weight of the block is =mg = 6kg × 10 ms-2 = 60 N
Since it was raised and dropped back to it's original position, distance = 5.3 × 2 = 10.6 m
Work done = 60N × 10.6 m = 636 J
A toy rocket fires its engines to launch it straight up from rest. After a short time, the engine turns off and the
rocket continues before falling back to the ground. The velocity - time graph for the rocket's complete
journey is shown
At what time after launch does the engine turn off?
Answer:
at 10 seconds.. b/c that's when the velocity stops increasing..
Explanation:
Attached here is the question:
Answer:
t = 6 [s]
Explanation:
In order to solve this problem we must first use this equation of kinematics.
[tex]v_{f}^{2}=v_{o}^{2} +2*a*x[/tex]
where:
Vf = final velocity = 0 (the car comes to rest)
Vo = initial velocity = 72 [km/h]
a = acceleration [m/s²]
x = distance = 60 [m]
First we must convert the velocity from kilometers per hour to meters per second.
[tex]72 [\frac{km}{h}]*\frac{1000m}{1km} *\frac{1h}{3600s} =20 [m/s][/tex]
[tex]0=(20)^{2} -2*a*60\\400 = 120*a\\a=3.33[m/s^{2} ][/tex]
Now using this other equation of kinematics.
[tex]v_{f}=v_{o}-a*t[/tex]
0 = 20-3.33*t
t = 6[s]
HELP?
if there is a junction with 4 wires and two of the wires are bringing in a current of 10 A and 7 A respectively, what would the combined amount of current coming out of the other two wires be?
If someone could explain to me, that'd be appreciated!
Answer:
17 A
Explanation:
hope it helps you
17 a is correct
There must be 17A flowing out of the other two wires
Electric current is a stream of moving electrons.
The number of electrons that leave a point has to be the same as the number of electrons that arrive there.
. If they arrive and don't leave, then there has to be a way to store them there, like a capacitor or a battery.
And if they're leaving but not arriving, then there has to be a tiny factory there, manufacturing electrons and shipping them out.
The whole idea is called "Conservation of electric charge". The idea is that charge can't be created or destroyed. If charge appears, it had to come from somewhere. And if you have some that you don't want, you have to send it somewhere, because it never just disappears.
There's actually a law in electronics that covers this nicely, called Kirchhoff's current law. It says that the sum of all currents entering a single point is zero. (current coming in is positive, current going out is negative). In other words, All current In and all current Out are equal.
The point of a nail has an area of 0.25cm squared, and an average person has a weight of 700 N. Explain in detail why it is possible to lie on a bed of 4000 nails, but not on one single nail. Thanks
Answer:
It is possible to lie on a bed of 4000 nails, but not on one single nail because a bed of 4000 nails exerts lesser pressure than a bed of one single nail .
Explanation:
Given;
weight of an average person, W = F = 700 N
area of the nail, A = 0.25 cm² = 0.25 x 10⁻⁴ m²
The pressure exerted by a single nail is given as;
P = F / A
P = 700 / (0.25 x 10⁻⁴)
P = 2.8 x 10⁷ N/m²
The pressure exerted by 4000 nails is given as;
Total surface area of 4000 nails = 4000 x 0.25 x 10⁻⁴ m² = 0.1 m²
P = F / A
P = 700 / 0.1
P = 7,000 N / m²
From the calculated values, 4000 nails exerts less pressure on the person than one single nail because pressure decreases with increase in surface area of an object.
Thus, it is possible to lie on a bed of 4000 nails, but not on one single nail because a bed of 4000 nails exerts lesser pressure than a bed of one single nail .
Two iron bolts of equal Mass one at a hundred see another at 55 Sierra place in the insulated cylinder assuming the heat capacity of the container is negligible what is the final temperature inside the container
Answer:
[tex]T_2 = 77.5c[/tex]
Explanation:
From the question we are told that
Temp of first bolts[tex]T_1=100[/tex]
Temp of 2nd bolt [tex]T_2=55[/tex]
Generally the equation showing the relationship between heat & temperature is given by
[tex]q=cm \triangle T[/tex]
Generally heat released by the iron bolt = heat gained by the iron bolt
Generally solving mathematically
[tex]-(0.45*m* (T_2-100 \textdegree c)) = 0.45*m*(T_2 -55\textdegree c)[/tex]
[tex]-(T_2-100 \textdegree c)) = (T_2 -55 \textdegree c)[/tex]
[tex]T_2 +T_2= 100 \textdegree c+55 \textdegree c[/tex]
[tex]T_2=\frac{155 \textdegree c}{2}[/tex]
[tex]T_2 = 77.5 \textdegree c[/tex]
Therefore [tex]T_2 = 77.5 \textdegree c[/tex] is the final temperature inside the container
Calculate the change in time for each quarter of the track. Record the change in time in Table C of your Student Guide
Answer:4 and 5
Explanation:it you add 1+3 and 2+3 it is 4 and 5
Pedro has collected different kinds of rocks. He begins testing the rocks' hardness to see how they compare.
What is the best phrase to describe what Pedro is doing?
A.
asking a question
B.
conducting a scientific investigation
C.
reporting scientific results
D.
forming a prediction
Answer:
B is the answer to the question
what is the relationship between frequency and wavelenghts of an EM wave?
A.as wavelengths decreases, the frequency of the waves increases.
B.as wavelengths decreases,the frequency also decreases
C.the wavelength and the frequency has a direct relationship
D.there is no relationship existing between wavelength and frequency
Answer:
a...as wavelengths decreases ,the frequency of the waves increases.Please help me with this question
Explanation:
I think the answer is 3/5
The brakes on a 15,680 N car exert a stopping force of 640 N.
The car's velocity changes from 20.0 m/s to 0 m/s. What is the
mass of the car? (Estimate 10 N/kg for g.)
Answer:
1568 Kg is the answer
Explanation:
What is vertical motion
the movement of an object in a straight line. When an object is thrown up, it always comes down, this is due to gravity
A 747 requires a takeoff speed of 270 meters per second if it is to get off the
ground. Calculate the acceleration required for the 747 that begins from rest
to takeoff on a 1000 meter long runway.
Answer:
a = 36.45[m/s²]
Explanation:
We can calculate the acceleration value by means of the following expression of kinematics.
[tex]v_{f}^{2} =v_{o}^{2} +2*a*x[/tex]
where:
vf = final velocity = 270 [m/s]
Vo = initial velocity = 0 (begins from rest)
a = acceleration [m/s]²
x = distance required by the plane = 1000 [m]
[tex](270)^{2} =0+2*a*1000\\72900=2000*a\\a=36.45 [m/s^{2} ][/tex]
A dragster finishes a race with a speed of 50 meters per second. The driver
deploys a drag chute which slows the car at a rate of -15 meters per second2.
Calculate the stopping distance of the dragster if only the drag chute is used
bring it to rest.
Answer:
83.3m
Explanation:
From the question we are given the following:
initial speed u = 50m/s
acceleration a = -15m/s²
final speed = 0m/s
Required
Stopping distance S
Using the equation of motion:
0² = 50²+2(-15)S
0² = 2500 - 30S
-2500 = -30S
S = 2500/30
S = 83.3m
Hence the stopping distance of the dragster if only the drag chute is used bring it to rest is 83.3m
Name ten scalar quantity and explain them
Answer:
A scalar is a quantity that is fully described by a magnitude only. It is described by just a single number. Some examples of scalar quantities include speed, volume, mass, temperature, power, energy, and time.
Examples of scalar quantity are:
Distance.
Speed.
Mass.
Temperature.
Energy.
Work.
Volume.
Area.
Explanation:
please mark me as brainliest thank you
The use of force to move an object is BLANK .
Answer:
Work
Explanation:
The use of force to move an object is the definition of "work" in physics.
Answer:
the answer should be wave
A car of mass 700 kg and movie at a speed of 30 m per 2nd collides with a stationary truck of mass 1400 kg and the 2 vehicles locked together on impact and the combined velocity of the car and the truck after the collision is what
Answer:
10m/s
Explanation:
(m1)(v1)+(m2)(v2)= (m1+m2)(v[final])
(700)(30)+(1400)(0)= (700)(v)+(1400)(v)
21000= 2100v
v=10m/s
A sloth moves 3 m to the right and then climbs 4 m up a tree.
How many degrees above the ground is the sloth compared to its initial position?
Answer:
The answer is 53.13
Explanation:
Cuz it is. It's not that hard
Answer:
A sloth moves 3 M to the right and then climbs 4 m up a tree.
How many degrees above the ground is the sloth compared to its initial position?
Answer: 53.1°
1. You take a trip to Philadelphia to see a concert. Your older friend drives you there. The
concert is 75 miles away, and you make it there in and two hours. What was the average
speed?
Answer:
37.5
Explanation:
divide
In this activity, you will research how scientists developed historical
models of the atom and present your findings. In the process, you
will draw evidence from texts to support analysis, reflection, and
research
Answer: Bohr's model (1913)
Niels Bohr improved Rutherford's model. Using mathematical ideas, he showed that electrons occupy shells or energy levels around the nucleus. The Dalton model has changed over time because of the discovery of subatomic particles.
Bohr's model (1913)
Niels Bohr improved Rutherford's model. Using mathematical ideas, he showed that electrons occupy shells or energy levels around the nucleus. The Dalton model has changed over time because of the discovery of subatomic particles
Dalton's atomic theory proposed that all matter was composed of atoms, indivisible and indestructible building blocks. While all atoms of an element were identical, different elements had atoms of differing size and mass.
John Dalton
The idea that everything is made of atoms was pioneered by John Dalton (1766-1844) in a book he published in 1808. He is sometimes called the "father" of atomic theory, but judging from this photo on the right "grandfather" might be a better term.
Explanation:
What is the block of 10 columns in the
middle of the table called?
A. Representative metals
B. Transition metals
how would u describe color to a color blind person?
Jose has two bar magnets. He pushes the ends of the two magnets together and then lets it go. The magnets move quickly apart. Which of the following statements best explains why this happens
A.The north poles of the two magnets are facing each other.
B.One magnet is a north pole & one magnet is a south pole.
C.The ends of the magnets repel each other but the centers attract. D.One magnet is storing energy & one magnet is releasing energy.
Answer:
A. like poles repel or push apart
dimension for weight
Answer:
What is meant by
Explanation:
Dimensions
Answer:
The dimension of weight is MLT−2: mass times acceleration, that is, a force.
Explanation:
hope this will help you