Question

A 64-kg ice skater at rest throws a 4 kg rock at 2 m/s. What is the resulting speed of the ice-skater in m/s?

Answer 1

Below

Step-by-step explanation:

Using law of conservation of momentum

Momentum before rock throw = momentum after rock throw

mv = mv

0 = -64 kg (x m/s) + 4 kg ( 2 m/s)

0 = -64 x + 4 * 2

64x = 8

x = 8/64 = 1/8 m/s ( in the opposite direction of rock)