00:01
Hi there, so for this problem, we are told that an athlete leaves one end of a pool of length health at a time is equal to zero and arrives at the other end at a time t.
00:14
She swims back and arrives at the starting point position at the times t.
00:21
Now, if she is swimming initially in the positive x direction, we need to determine her average velocities symbolically for part a the first half of the swim.
00:37
So for that we use just simply the definition of velocity.
00:42
So the velocity one, the average velocity one in the adstruption, is equal to the change in the position we're going to call one divided by the change in the time one.
00:57
So that will be the final length in here, which is the length l minus the initial position which is zero, this divided by the interval of time, that is just simply the time one.
01:11
So from this, we obtain that this is the length l divided by the time one.
01:16
This is positive.
01:18
Now, for part b of this problem, we are asked about the second half of the swim and the rome 3.
01:27
So with that said, this speed, the average is b2 is going to be equal to the change in the position 2 divided by the interval of time 2.
01:41
So in here we will have.
01:43
So now the final position is 0 and the initial position is l, and this divided by the interval of time that we're going to call the times 2.
01:53
So that will be minus l divided by the time 2.
01:58
Now, for part c of this problem, we are asked about the round trip...