Question

A spherical ball of mass 10-6 kg hits a wall 1000 times per second normally with a velocity of 1000 m/s and rebounds with same velocity along the initial direction. The force experienced by the wall is:

Answer 1

Answer:

Velocity of body initially u=100

i

^

m/s

After bouncing, the body will move with same speed but in opposite direction.

Velocity of body finally v=−100

i

^

m/s

Mass of body m=2 kg

Change in momentum of the body Δp=m(v−u)=(2)(−100−100)

i

^

=−400

i

^

kg m/s

Magnitude of change in momentum ∣Δp∣=400 kg m/s

Time of contact Δt=

50

1

s

Force exerted on the wall F=

Δt

Δp

=

(1/50)

400

=2×10

4

N