Question

A freely falling body reaches the ground after 4 second.what is the height at which reaches

Answer 1

Answer:

78.4m

Explanation:

Given,   t=4 sec ;     a=g (freely falling) = 9.8m/s^2 (Not given that's why take this);    u=0  

So according to 1st equation of kinematics =

S = ut + $\frac{1\\}{2}$ a$t^{2}$               => 0*4 + 1/2 * 9.8 * ($4^{2}$)

  => 0 + 1/2 * 9.8 * 16              => 78.4 m

Height from which it fallen = 78.4m