00:01
In this question we have three parts, part a, b and c.
00:04
Let's write the values that are given to us for part a.
00:08
So firstly, m1 is equal to 30, 30 gram, then v1, 4 meters per second.
00:28
M2, 47 gram, v2 minus 7 meters per second, since in other direction.
00:41
Now we apply the law of conservation of momentum.
00:46
We have m1 times v1 plus m2 times v2 is equal to m1 times v1 plus m2 times v2 in the values we have 30 times 4 plus 47 times minus 7 is equal to 30 times minus 7 5 4 plus 47 times v2 simplifying this will give us v2 to exactly 17 .2 over 47 v2 is equal to 0 .365 meters per second this is our answer for part a now let's work on part b so for part b before collision the kinetic energy is half m1 v1 square plus half m2 v2 square this is equal to exactly half 30 times 4 square plus half 47 times minus 7 this is equal to 240 plus 1151 .5 this is equal to 240 plus 1151 .5 this is equal to 1391 .5 joules.
02:35
This is the kinetic energy before collision.
02:37
Now after collision is equal to half m1 v1 square plus half m2 v2 square.
02:57
Now putting the values.
03:00
This is equal to exactly 1 over 2 times 30 times minus 9 .4285 square plus half half times 47 times 1 .5714...