Question

A soccer ball is traveling at a velocity of 50 m/s. The kinetic energy of the ball is 500 J. What is the mass of the soccer ball? (Formula: )

A 0.1 kg
B 0.2 kg
C 0.4 kg
D 0.5 kg

Answer 1

Given : v=30 m/s t=0.1 s m=0.25kg

The ball bounces back with same speed after hitting the wall.

Thus change in its momentum ΔP=mv−(−mv)=2mv=2×0.25×30=15 kg.m/s

Using ΔP=∣F∣t

∴ 15=∣F∣×0.1 ⟹∣F∣=150 N

Thus the force exerted by the wall on the ball F=−150 N

Answer 2

Kinetic energy = 1/2*m*v^2
500=1/2*m*50^2
500=1/2*m*2500
500=m*1250
m=500/1250
m=0.4 kg
There’s your answer mate

Hope it helped!!