A0.0427 kg racquet-ball is moving
22.3 m/s when it strikes a
stationary box. the ball bounces
back at 11.5 m/s, while the box
moves forward at 1.53 m/s. what
is the mass of the box?
(unit = kg)

Mass of the box = 0.9433 kg

Explanation:

Mass of racket-ball = 0.00427 kg

Velocity of racket-ball before collision = 22.3 m/s

Velocity of racket-ball after collision with box = -11.5 m/s

[Since ball is bouncing back, so velocity is taken negative.]

Velocity of the box before collision = 0 m/s

[Since the box is stationary, so velocity is taken zero]

Velocity of box moving forward after collision = 1.53 m/s

To find the mas of the box .

By law of conservation of momentum we have:

Momentum before collision = Momentum after collision

This can be written as:

We can plugin the given value to find

Adding both sides by 0.4911

Dividing both sides by 1.53.

∴ kg

Mass of the box = 0.9433 kg (Answer)