00:03
Hello, so we have the height of the cliff being 2 .57 times 10 to the power minus 16 of an eta meter.
00:26
Because it is 10, 10 to the power 18.
00:36
So this gives us 257 meters as the height of the cliff.
00:47
The initial velocity is 4 .3 to.
00:55
Kilometers over 60 seconds.
01:01
So that is 72 meters per second.
01:06
So our projectile is fired from the top of a cliff.
01:19
That is on 257 meters high.
01:26
We found initial velocity of 72 meters per second making an angle of 7 meters per second making an angle of 7.
01:36
6 to 6 degrees to the horizontal.
01:40
So first of all we're going to find the time it takes to hit the ground.
01:45
We use the formula s equals s note plus vyt and it's half t squared projectile formula.
02:01
S is the final displacement when it hits the ground.
02:04
Since the ground is a reference point when it's on the ground displacement is zero.
02:09
S not is any original displacement above the ground before the motion started.
02:14
So in this case, s not is the displacement 257 or the height of the projector at time t equals you.
02:25
Vy is the vertical component of velocity which is which is vertical component of velocity is 72, 6 to 6.
02:40
Horizontal component is 72 called 66 and so this 72 sign 6.
02:51
Minus 5 ,9 .8 t squared.
02:56
This comes down to a quadratic equation in t, for which we have two answers.
03:10
T equals 16 .6 seconds and also minus 3 .2 seconds.
03:18
Of course, we take the positive one and is the negative.
03:25
For b, we are to find a range.
03:27
The range is simply the horizontal velocity...