00:01
So in this question as you see, a ball is thrown vertically upward from the ground level with the initial velocity of 128 feet per second.
00:10
So over you would be minus 128 feet per second since we are throwing it upwards, right? so what else is given to us? assume the acceleration of the ball is at 32 feet per second square.
00:29
So our a is 32 feet per second square.
00:37
This is the a.
00:42
Now, first question is, how long will it take the ball to rise to its maximum height? so maximum height has to be found out first.
00:51
So in order to find out the maximum height, that is s.
00:54
Okay, so we have the formula.
00:56
S is b8 plus half 80 square.
00:59
Or we can also use b is equal to u plus 80.
01:05
That also we can do.
01:06
But now, and also we have v squared minus u square is equal to 2 as.
01:13
These are the equations of motion that we have.
01:17
Now, i'm going to take, let this be the second, let this be the first equation, let this be the third equation.
01:25
So taking the third equation, that is v squared minus u square equal to 2 as.
01:36
So here u is given to us and when b comes it will be zero, right? so we would be equal to 0.
01:43
Now, i'm putting 0 here.
01:46
So minus of minus 128 the whole square is equal to 2 into 8, s, right? so we put it like this, 128 into 128 equal to 64 into s.
02:08
So we can cut it from here.
02:10
It's except for s can be written as 128 into 128.
02:17
Divided by 64...