Question

Sheila weighs 60 kg and is riding a bike. Her momentum on the bike is 340 kg • m/s. The bike hits a rock, which stops it completely and throws Sheila forward onto the pavement.

If there is no net force on the system, what is Sheila’s velocity immediately after she is thrown from the bike?

1.8 m/s
2.0 m/s
5.0 m/s
5.7 m/s

Answer 1

Momentum is conserved. Sheila's momentum must equal 340 kg·m/s, so v = p/m = 340 / 60 = 5.666... m/s ≈ 5.7 m/s.

Answer: 5.7 m/s (forward).