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.
Answer:
the magnitude of the work done by the two blocks is the same.
Explanation:
The work done by block a on block b is given by:
where Fa is the force exerted by block a on block b, and d is the distance they cover.
The work done by block b on block a is given by:
where Fb is the force exerted by block b on block a, and d is still the distance they cover.
For Newton's third law, the force exerted by block a on block b is equal to the force exerted by block b on block a, therefore
and so