Question

A child drops a ball from a height of 10 m. Assume that its velocity increases uniformly at the rate of 10 m per second squared. Find the velocity with which the ball strikes the ground and the time taken by the ball to reach the ground.​answer = 14.14

Answer 1

ball starts from rest so u=0
acceleration=10m/s
height=10m
v^2=u^2+2ah
v^2=0+2×10×10
v=14.14m/s

Answer 2

    ⒶⓃⓈⓌⒺⓇ    

Acceleration(a) = 10 m/s²

Initial Velocity(u) = 0 m/s

Final velocity be 'v' m/s

g = 10 m/s²

Now Using equation of motion:

v² + u² = 2gh

v = √2gh

  = √200

  =  10√2 m s⁻¹

Now, Let the time be 't' sec.

Equation of motion:

  h = ut + 1/2gt²

⇒h = 1/2gt²

⇒t = √(2h/g)

⇒t = √2 sec

∴ Velocity = 10√2 m s⁻¹

∴ Time = √2 second