Answer:
Speed, v = 5 m/s
Explanation:
We have,
The length of the football field, l = 100 m
A person takes 20 seconds to run its length.
It is required to find the speed of the person with which he should run. The distance covered divided by time taken is called its velocity.

So, the speed of the person is 5 m/s.
A plane mirror forms a virtual image behind the mirror. The image is as far behind the mirror as the object is in front of it. A cannot see his image because the length of the mirror is too short on his side. However, he can see the objects placed at points P and Q, but cannot see the object placed at point R
Hope this helps Buddy!
~ Courtney
Answer:
V = 6.65 [volt]
Explanation:
First, we must calculate the power by means of the following equation, where the voltage is related to the energy produced or consumed in a given time.
![P=E/t\\P = 40/30\\P = 1.33[s]](https://tex.z-dn.net/?f=P%3DE%2Ft%5C%5CP%20%3D%2040%2F30%5C%5CP%20%3D%201.33%5Bs%5D)
Using the power we can calculate the voltage, by means of the following equation that relates the voltage to the current.

where:
V = voltage [Volts]
I = current = 200 [mA] = 0.2 [A]
![V = 1.33/0.2\\V = 6.65 [volt]](https://tex.z-dn.net/?f=V%20%3D%201.33%2F0.2%5C%5CV%20%3D%206.65%20%5Bvolt%5D)
The speed does the block move after it is hit by the bullet that remains stuck inside the block will be 23.7 m/sec and it takes 12.07 seconds to stop.
<h3>What is the law of conservation of momentum?</h3>
According to the law of conservation of momentum, the momentum of the body before the collision is always equal to the momentum of the body after the collision.
Apply the law of conservation of momentum principle;
m₁v₁+m₂v₂cosΘ =(m₁+m₂)V
3 kg × 12 m/s + 0,1 kg × 400 m/s cos 20° = (3+0.1)V
36 + 40 cos 20° = 3.1 V
V=23.7 m/sec
The time it takes to stop when the friction coefficient between the block and the surface is 0.2 is found as;
V = u +at
V = 0+ μgt
23..7=0.2× 9.81 ×t
t=12.07 sec
Hence, it takes 12.07 seconds to stop.
To learn more about the law of conservation of momentum refer;
brainly.com/question/1113396
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