## Kumar Ketan is teaching live on Unacademy Plus

Home ExploreSearch Courses, Topics &Educators 0 minutes today Kumar Ketan Hey, this is kumar Ketan. I'm graduate in physics and doing further studies. I Edit Profile would love to teach you and give you all my knowledge. 415 Views in last 30 days 1,377 Lifetime Views 7 Courses 499 Followers Following Course Overview Expected topics of Current Affairs for SSC/1BPS/UPSC/PCS/UPPSC/ALL OTHER GOVERNMENT EXAMS with some details COLLISION A col ision as an isolated event in which two or more colliding bodies exert relatively strong forces on each other for a relatively short time CURRENT AFFAIRS Expected topics of General Awareness for UPSC CSE/SSc/ Railway with some details Collision between particles have been divided broadly into two typer: 1. Elastk collision st VOTE enroll By Kumar Ketan By Kumar Ketan By Kumar Ketan (Hindi) Collision for IIT JEE (Hindi) Current Affairs 2018 for UPSC CSE (Hindi) General Awareness: Most Important 50 Question for. 23 Lessons 6 Lessons https://unacademy.com/user/KumarKetan

Two masses "m" and "2m" are placed in fixed horizontal circular smooth hollow tube of radius "r" as shown in figure. The mass m is moving with speed "u" and the mass "2m" is stationary. After their first collision, the time elapsed for next collision. (coefficient of restitution e-1/2) IT JEE 2004 27r 37tr

Solution: 2 m

Let the speed of balls of mass m and 2m after collision be vi and v2 as shown in figure. Applying conservation of momentum 2

7 u1UL2 202-201 = - u 7 7 Solving we get v 0 and v2- V212 now time Ttr 7 At

A plastic ball falls on a floor with speed v and then rebounds vertically. process is repeated a number of times till the ball stops. If the coefficient of restitution is e, then what is the total momentum imparted by the plastic ball to the floor? The (a)p(ite) 1- (d) p

Solution: When a particle undergoes normal collision, the speed of particle after the collision is "e" times the speed before collision, Initial momentum p-mv change in momentum after first impact change in momentum after second impact change in momentum after third impact therefore, total momentum imparted ep(-p)p (1+e) = e (ep)-(ep) = ep (1+e) e p (1+e) p (1+e) (1tee..

we use G.P =a+ar+ar2 + = { } where a is first term and r is common ratio =p(1+e) 1+e