Two figure skaters stand on perfectly frictionless ice
PHYSICS · Multi-part · AP · Physics 1: Algebra-based · Force and Translational Dynamics · Force and Translational Dynamics
Problem
Two figure skaters stand on perfectly frictionless ice. Skater A has a mass of 50kg and Skater B has a mass of 70kg. They face each other, initially at rest and touching palms. Force sensors in their gloves measure that Skater A exerts a constant 150N horizontal force on Skater B for a time interval of 0.60s. After that interval, the skaters lose contact and coast freely.
(1) Part 1: State the relationship between the force exerted by Skater A on Skater B and the force exerted by Skater B on Skater A during the 0.60s interval, and justify your answer.
(2) Part 2: Calculate the magnitude of the horizontal acceleration of each skater while the forces are acting.
(3) Part 3: Determine the speed of each skater immediately after they separate.
(4) Part 4: Treating the two skaters together as a single system, show mathematically that the internal forces between them do not affect the horizontal motion of that combined system.
(5) Part 5: Explain, in words, how your result in part (d) resolves the apparent paradox of “equal and opposite forces” producing motion when the two skaters are considered separately.