Question

A man standing on the edge of a Cliff throws a stone straight up with initial speed u and then throws another stone straight down initial speed u from the same position.Find the ratio of speeds,the stones would have attained when they hit the ground at the base of the cliff?

Answer 1

Answer:

1:1

Explanation:

Speed of a particle (magnitude of velocity) is the same at same height. So, when the man throws the ball with speed u, it will return to him with the same speed u.

v=u+at

=>0=u-gt (final velocity on reaching the top is 0,-ve sign due to downward acceleration)

=>u=gt ---------(i)

While coming down

v=u+at

=>-v=0-gt (-ve sign due to downward direction)

=>v=gt  ------(ii)

from (i) and (ii), lvl=lul

So when man throws the stone upward with speed u and downward with speed u, the initial velocity (from the cliff) will be the same. Hence, this will result in equal final velocity.

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