Question

A ball is gently dropped from a height of 20m if its velocity increases uniformly at a rate of 10 metre per second square with what velocity will it strike the ground after what time will it strike the ground​

Answer 1

Given,

Distance (s) = 20 m

Accelaration (a) = 10 m/s²

Initial Velocity (u) = 0 m/s

Final velocity (v) = ?

Time (t) = ?

We know,

v² - u² = 2as

v² - 0 = 2 * 10 * 20

v² = 400

v = √400

v = 20 m/s

And, 

v = u+at

20 = 0 + 10 * t

20 = 10 t

t = 2 second

∴ Striking velocity = 20 m/s

∴ Striking time = 2 second

hoping it helps you :-)

Answer 2

Hope it's will help you!!!!