Two ice skaters suddenly push off against one another starting from a stationary position.The 45-kg skater acquires a speed of 0.375 m/s relative to the ice.What speed does the 60-kg skater acquire relative to the ice?
A)0.50 m/s
B)0.28 m/s
C)0.38 m/s
D)0.75 m/s
E)0.00 m/s

Question

Quizplus · Accepted Answer

By conservation of momentum, the total momentum of the system before and after the push off must be zero. Let the velocity of the 60-kg skater after the push off be v. Then, we have:
(45 kg)(0 m/s) + (60 kg)(0 m/s) = (45 kg)(-0.375 m/s) + (60 kg)(v)
Solving for v, we get v = 0.28 m/s. Therefore, the 60-kg skater acquires a speed of 0.28 m/s relative to the ice. The correct choice is B.

Two Ice Skaters Suddenly Push Off Against One Another Starting