00:02
Alrighty, so starting with part a, to measure how far the ball will fall, or the change in distance, we're going to set that equal to one -half gravity times the time it's falling squared, plus an initial velocity times time.
00:26
So for this part, we're going to assume that it's falling for three seconds, but since it's falling from rest, we're also going to say that the initial velocity is zero.
00:38
So we don't need to consider this term.
00:41
So instead, we'll just say that delta x is equal to one -half, gravity is 9 .8.
00:50
And the time here, i'm going to say is three seconds squared.
00:56
If you plug that into your calculator, you'll get approximately 44 .1.
01:03
Meters is how far it will have fallen.
01:07
So that's part a.
01:10
For part b we want to know the final velocity after it has fallen for 2 .5 meters.
01:19
So let's use this equation where our final velocity squared is equal to our initial velocity squared plus two times the acceleration, which is g in this case, times the distance.
01:39
Once again, this initial velocity is zero.
01:44
So our final velocity squared is equal to 2 times 9 .8 times that 2 .5 meters.
01:58
Let's scroll down a little bit.
02:03
And when we plug that into our calculator, that's equal to 49...