00:02
In this question, we have a ball of 0 .2kg ball moving to the right with 1 .5 meters per second and then there's another ball .3 kg moving to the left with a speed of 0 .4 meters per second.
00:23
And then they have elastic collision.
00:26
So in part a, we want to find the velocities after the collision.
00:36
So conservation of momentum for the two ball system, we get.
00:56
So i'm going to take right to be positive.
01:02
So 1 .5 times 0 .2 plus, sorry, minus 0 .3 times 0 .4 is equal to m1 this is 1 this is 2 m1 v1 f plus m2 v2 f okay so putting in the numbers we get 2 v1f plus 3 v2 f equals to 1 .8 okay so this is equation 1 okay the next equation would be relative speed of approach equals to relative speed of separation, relative speed of separation.
02:06
So this gives v1i minus v2i vector equals to v2f minus v1f in vector.
02:18
Okay, so i'm going to take again right to be positive.
02:25
So we have v2f minus v1f equals to 1 .5, minus 0 .4, this is 1 .9.
02:36
So this is our second equation.
02:44
So we first eliminate v1f.
02:56
So v1f can be eliminated by multiplying equation to equation 2 by 2 and then add 1 and 2 together.
03:06
And then we have 5...