00:01
Hello.
00:02
So for the first part of the question we can use v equals u plus at.
00:10
Okay, so because the car is going to stop, this guy is going to go to zero.
00:16
So we're going to have zero equals u.
00:19
Now we have deceleration, so that's minus a t.
00:23
So the time you want is going to be u over a.
00:29
So our initial velocity is 24 .6.
00:36
Our acceleration is 4 .92 and so t will be 24 .6 divided by 4 .92.
01:01
It's a very nice number, so just five seconds.
01:09
So this is the a part of the question b is asking for the, how far does it travel in this time? so we can use s equals ut minus half ut squared.
01:33
Initial velocity is, what is that? so we have 24 .6 times 5 minus half times acceleration is 4 .92 times 5 squared.
02:00
So we have 24 .6 times 5.
02:08
That's 1, 2, 3 minus that times 4 .92 plus 61 .5.
02:30
Okay.
02:31
So 1, 2, 3 minus 61 .5 and 61 .5.
02:40
Okay, so that's how 5 travels.
02:43
Let's look at c...