Question

10. A child drops a ball from a window. The ball strikes the ground in 3.0 seconds. What is the velocity of the ball the instant before it hits the ground?

Answer 1

Answer:

Acceleration(a) = 10 m/s²

Initial Velocity(u) = 0 m/s

Final velocity be 'v' m/s

g = 10 m/s²

Now We can use 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 ← (Answer)

∴ Time = √2 second  ← (Answer)

Answer 2

Answer:

Acceleration

v=u+at

v=0+10x3

• v=30m/s²

Explanation: