PHYSICS · Multi-part · AP · Physics 1: Algebra-based · Force and Translational Dynamics · Force and Translational Dynamics
Problem
Two skaters, A and B, stand a short distance apart on perfectly smooth, horizontal ice. Skater A has mass 60kg and skater B has mass 40kg. Both are initially at rest with respect to the ice. They push each other apart for a very short time and then glide freely until they come to rest again relative to the ice. After the push, the distance between the two skaters has increased by 1.5m.
Answer the following questions.
(i) During the brief interval of pushing, identify the action force and its corresponding reaction force.
(ii) Derive an expression for the ratio of the distances moved by skater A and skater B from their common initial position.
(iii) Calculate the individual distances travelled by skater A and by skater B.
(iv) Explain why the centre of mass of the two-skater system remains at the same point on the ice throughout the motion.