Question

A ball is released from the top of a tower of height $h$. It takes time $T$ to reach the ground. What is the position of the ball from ground after time $\frac{T}{3}$?

• A. $\frac{h}{9}m$
• B. $\frac{7h}{9}m$
• C. $\frac{8h}{9}m$
• D. $\frac{17h}{18}m$

Answer 1

The correct option is C $\frac{8h}{9}m$

As the ball is released from rest initially
$\Rightarrow u=0$
If total height $h$ fallen in $T$ time then the relation is given by using second equation of motion as
$h=\frac{1}{2}g{T}^2$
Now if time will be $\frac{T}{3}$ then
The distance fallen $=\frac{1}{2}g{\left(\frac{T}{3}\right)}^2=\frac{h}{9}$
So position of the ball from the ground
$=h-\frac{h}{9}=\frac{8h}{9}m$