Question

from the top of a tower of height h, a body is thrown vertically downwards with an initial velocity u. Simultaneously another body is thrown vertically upwards with an initial velocity u. In reaching the ground the additional time required by the body thrown upwards is?

Answer 1

Given,
Height of tower=h
Initial velocity in both the cases=u
Here,
The addition time or time difference of reaching ground between both the bodies=Time taken by second body to return at the point of projection
For the second body,
Upward motion,
v=0
Using, v=u-gt
0=u-gt
or t=u/g
Time taken for this body for downward motion i.e to return at the point of projection will be same.
Thus,
Total time=2u/g
Therefore, the required additional time=2u/g