Question

Mixed-pair ice skaters performing in a show are standing motionless at arms length just before starting a routine. They reach out, clasp hands, and pull themselves together by only using their arms. Assuming there is no friction between the blades of their skates and the ice, what is their velocity after their bodies meet?

a) Same as initial velocity.
b) Greater than initial velocity.
c) Less than initial velocity.
d) Zero velocity.

Answer 1

The velocity of the ice skaters after they meet is zero due to the conservation of momentum and the absence of external forces such as friction, resulting in the system's total momentum remaining unchanged.

Step-by-step explanation:

The question pertains to the conservation of momentum principle in physics. When the mixed-pair ice skaters standing motionless at arms length pull themselves together, they are subject to internal forces only, and since there is no friction between the blades of their skates and the ice, the external forces are negligible. Conservation of momentum dictates that the momentum of the system before and after the skaters meet must be equal.

Assuming they have equal mass and they pull with equal force, their velocities towards each other will be equal and opposite, which cancels out the total momentum of the system to be zero before they meet. Therefore, their velocity after their bodies meet is also zero, because the system’s total momentum remains unchanged.

Thus, the answer is (d) Zero velocity.