Question

A ball is dropped from the top of a tower of height 'h'. It takes time 'T' to reach the ground. The position of the ball after time $(\frac{T}{3})$ is (from the ground)

• A. $\frac{2h}{9}$
• B. $\frac{4h}{9}$
• C. $\frac{6h}{9}$
• D. $\frac{8h}{9}$

Answer 1

Answer: (D)

$\frac{8h}{9}$

Answer 2

For free fall, total time
   T = √(2h/g) ⇒ g = 2h/T².
At t = T/3, distance fallen:
   s = ½·g·(T/3)² = ½·(2h/T²)·(T²/9) = h/9.
Height from ground = h – (h/9) = 8h/9.