PHYSICS · Multi-part · AP · Physics 1: Algebra-based · Linear Momentum · Linear Momentum
Problem
Two carts move on a straight, horizontal, nearly frictionless track. Cart A has mass 0.50kg and moves to the right at 2.0ms−1. Cart B has mass 0.80kg and is initially at rest. The carts collide and latch together by means of Velcro in a perfectly inelastic interaction that lasts 0.050s. During the collision the track exerts a small constant friction force of magnitude 0.20N on the two-cart system.
(a) Identify a system for which total horizontal momentum is conserved throughout the 0.050s collision interval, and briefly justify your choice.
(b) Using your system from part (a), calculate the speed of the two-cart combination immediately after they latch together.
(c) A student instead ignores friction and treats only the two carts as the system. Determine the percent error introduced in the student’s answer for the final speed. Show your work.