00:01
Here we have to solve the following problem.
00:02
Ball, which has a mass of 0 .265 kilograms, makes an elastic head -on collision with a second ball which is initially at rest.
00:12
The second ball moves with a speed, which is one half of the original speed.
00:26
First, in question a, we have to find mass of the second ball in two.
00:31
Let's solve this problem.
00:33
Here, we have to realize conservation.
00:35
Conservation of momentum and conservation of energy.
00:39
Let's do this.
00:43
M1 times v1 initial equals to m1 v1 final plus m2 v2 final.
00:50
That's the conservation of momentum and now we have to write down conservation of the energy.
01:07
Now let's group this equation as following.
01:11
So we will group m1 on the left side and m2.
01:16
On the right side of this equation both equations now let's derive the second equation by the first and as we can see v1 initial is actually here is better to express v1 final which is v2 final minus v1 initial that is so that equals to v1 initial over 2 minus v1 initial which is negative v1 initial over 2.
02:47
Okay, now we found the relationship between v1 final and v1 initial and now we can get back to equation number 1 to calculate m2 here m2 is m1 times v1 initial minus v 1 final divided by v2 final...