Two identical ice skaters of negligible size stand 3.0 m apart on a frictionless…
PHYSICS · Multi-part · AP · Physics 1: Algebra-based · Force and Translational Dynamics · Force and Translational Dynamics
Problem
Two identical ice skaters of negligible size stand 3.0 m apart on a frictionless frozen lake. They initially rest relative to the ice and are connected by a light rope held taut between them. Just after they simultaneously push off one another and release the rope, a gentle and steady cross-wind begins to exert a small horizontal force on only one of the skaters.
Answer the following questions about the system consisting of the two skaters.
(a) Before the push, describe the horizontal motion of the center of mass of the two-skater system. Justify your description in terms of external forces.
(b) During the brief instant while the skaters are pushing each other, explain whether any horizontal acceleration of the system’s center of mass occurs. Clearly account for the forces involved.
(c) After the skaters separate, but before the wind begins, compare the individual motions of the two skaters to the motion of the system’s center of mass. Provide a qualitative explanation.
(d) Once the cross-wind begins to act on only one skater, describe and justify how the subsequent motion of the system’s center of mass differs from its motion immediately after the push.