PHYSICS · Subjective · AP · Physics 1: Algebra-based · Linear Momentum · Linear Momentum
Problem
Two spheres, C (mass 1.0 kg) and D (mass 1.5 kg), approach each other on a smooth horizontal plane. Just before impact, C moves eastward at 3 m s⁻¹ while D moves westward at 2 m s⁻¹. A student claims that after a perfectly inelastic collision (the spheres stick together) the combined body moves northward with momentum 2.5 kg m s⁻¹.
(a) Show by direct calculation the magnitude and direction of the total momentum of the system just before collision.
(b) Examine the student’s claim by comparing the claimed post-collision momentum vector with the correct pre-collision vector. Identify the error in the claim.
(c) Draw a corrected momentum diagram for the system and state the true magnitude and direction of the velocity of the combined mass after the collision.