00:02
Okay, so in problem number four, problem number five, sorry, we are working with a volleyball that is being spiked back to an opponent and being asked what impulse the player needed to apply to the ball to create the change in velocity.
00:18
So let's start with the information that we were given in the problem.
00:21
We have the mass of the volleyball is 0 .35 kilograms.
00:26
We know the volleyball has an incoming velocity, or an initial velocity, vi, of positive 4 meters per second.
00:39
Okay, so we're going to keep track of our directional signs here.
00:43
In this case, the positive means that it's coming at the player spiking the ball.
00:49
So positive 4 meters per second.
00:51
We know that the player spikes the ball so that it has an outgoing velocity or a final velocity of negative 21 meters.
01:01
Per second.
01:03
And we are asked to find the impulse.
01:07
The book uses a capital j for impulse.
01:10
So we're going to find that.
01:11
Okay...