Question

3. A 5 kg particle moves in the +x direction with a velocity of 6 m/s shown in the figure below. You are told that it makes an elastic collision with a 2kg particle that is initially at rest. After the collision, the 2 kg particle moves with a speed of 5 m/s in the direction 30° above the x-axis. (a) What are the x and y components of the 5 kg particle after the collision? (20 points) (b) Were you informed correctly? Is there a percentage change in kinetic energy? (15 points) dm's INITIAL

Answer 1

t - X · 19, 20 1, = 6m|s $0 o Before collision Oana mot = 5 ms After collisioon u Initial momentum in x-direction = (6m/s) (5kg) to - 30 kg m/s fial momentum in *- direction = (5 cos30°) (2)kg mest + 8 x x 5kg final momentum in y- direction = (5 sin 30 (2) karls & Vlyx skj

Applying consewation of momentum in berth xfy diection (x-egh) 30 kg mit = 50 kg + 10 cosso" komst a 500 , 4 ky + 563 kgmst s. svik kg = (30-543) kg mst - 21.34 kgnst => 0M = 9.268 'm51) (Y- eg") = lo sin 300 kemst + 50 ly kg Svoris kg = - 10 () legms 7 1 x Ě 4.27 m/s Veig = -1mls viy is in negative sign shown that - ŷ direction

(b) Kimitil = {*5X02 I to = 90 I Kfinal = x2852 I + ¿xx(1+ 4.272) = 25. 48.089 = 73.08 I :| Kinetic energy befroe & after collision is not same , therefore we were informed Incorrectly . Collision is not elastic It's an inelastic collision % change in KE - K final -Kinitial - Xlo do 1. Kinitial 73.08 - 70 x 100 % go % change in KE = -16.92X100% = -18.8% ve sign shows decrease in KE. go