Question

A stone is thrown vertically upwards with an initial speed `u` from the top of a tower, reaches the ground with a speed `3 u`. The height of the tower is :
A. `(v^(2))/(g)`
B. `(2v^(2))/(g)`
C. `(4v^(2))/(g)`
D. `(8v^(2))/(g)`

Answer 1

Correct Answer - C
According to the third equation of motion
`v^(2)-u^(2)=2as` given `v=3v,u=v and a=g`
or `(3v)^(2)-v^(2)=2gs or s=(4v^(2))/(g)`