00:01
So in this question, we have an incoming ball of ball of mass 0 .22 kilograms, and it's moving at the speed of 5 .5 meters per second, and it climbs headlocked elasticly with another ball initially at rest.
00:21
After the collision, the incoming ball bounces back, with a speed of 3 .8 meters per second.
00:32
So we need to calculate the velocity of the target point.
00:34
After the collision.
00:36
So if this is this n -a, n -b, n -a is v -a -p -a -p -p -p.
00:42
We need to calculate what v -b -p -p - is, and then we need to know what the n -b is.
00:49
Okay, so first part, calculate the velocity of the target -ball after the collision.
00:56
What do we know already? we know m -a, we know m -b, we know v -a, we know v -b, and then we know v -a -prime.
01:03
So that is enough for us to use equation, 7 .7, that is the relative velocity equation.
01:12
We know that the relative velocity of the two balls before and after the collision will be equal and opposite.
01:20
So here, because we already know v -a -v -b and v -a -prime, we can find v -b -prime from this equation.
01:26
V -b is just 0.
01:28
So this gives us zp prime equals v -a plus v -a -prime.
01:38
B .a plus v8.
01:42
So this is 5 .5 meters per second minus.
01:49
It's the opposite direction, so minus meters per second...