Question

Two ice skaters want to prove conservation of momentum. Skater A has a mass of 72 kg, and skater B has a mass of 48 kg. They are originally at rest. They hold hands and face each other. They then push off each other and move in opposite directions. Skater B moves with a velocity of 3 m/s.

What must the velocity of skater A be in the opposite direction after the push in order to prove conservation of momentum?

(1 point)
Responses

1.5 m/s
1.5 m/s

2.0 m/s
2.0 m/s

4.5 m/s
4.5 m/s

3.0 m/s

Answer 1

Use conservation of momentum: 0 = m_A v_A + m_B v_B.
So v_A = −(m_B/m_A) v_B = −(48/72)·3 = −2 m/s.

Answer: 2.0 m/s (in the opposite direction).