A ball is gently dropped from a height of 20m. If its velocity increas

1.	A ball is gently dropped from a height of 20m. If its velocity increases uniformly at the rate of 10 ms-2 . With what velocity will it strike the ground? After what time will it strike the ground?
Answer» Given: height = 20 m acceleration = 10 ms Formula: For free falling body, 1. v = gt 2. s = 1/2 gt² time taken to strike the ground s = 1/2 gt² 20m = 1/2 × 10 ms^-2 × t² t² = \(\frac{40 m}{10 ms^{-2}}\)= 4s² ∴ t = 2s 3. Velocity of the ball when it strikes ground v = gt v = 10ms^-2 × 2s v = 20ms^-1

A ball is gently dropped from a height of 20m. If its velocity increases uniformly at the rate of 10 ms-2 . With what velocity will it strike the ground? After what time will it strike the ground?

Answer»

Given:

height = 20 m

acceleration = 10 ms

Formula:

For free falling body,

1. v = gt

2. s = 1/2 gt²

time taken to strike the ground

s = 1/2 gt²

20m = 1/2 × 10 ms^-2 × t²

t² = \(\frac{40 m}{10 ms^{-2}}\)= 4s²

∴ t = 2s

3. Velocity of the ball when it strikes ground v = gt

v = 10ms^-2 × 2s

v = 20ms^-1