00:01
Here we have a projectile motion problem.
00:02
And first, we want to find the speed of the plane from which the projectile is launched.
00:10
So to do that, what we can do is first think about how we can find one of the components of the velocity so that we can use trigonometry to find the velocity.
00:25
We know the time and we know the height.
00:27
So let's try to find the vertical component of velocity first.
00:36
Now we could use the following equation.
00:39
We can say that height is equal to the initial velocity in the y -axis, which is what we are trying to find, times the time, plus one half over multiplied, i'm sorry, by gravity times times squared.
01:00
Now notice that we're writing plus acceleration because we're defining down to be positive in this case.
01:08
So now when we try to solve for the initial velocity in the y -axis, we obtain that it is equal to the height divided by the time minus one -half times the gravity times the time.
01:31
And we have all the information to complete this equation.
01:33
We know that the height is 730 meters.
01:37
We know that the time is 5 seconds minus 1 half times gravity times the time and with that we obtain that the velocity is almost 121 .5 meters per second now as we said we can use our trigonometry to find the speed of the plane so we know that cosine of theta is equal to the adjacent over the hypotenuse and the adjacent is a hundred and twenty one point five meters per second over the hypotenuse which is the speed of the plane and we know the angle it's 53 degrees so when we solve for the velocity or the speed and we use the 53 degrees we obtain that that velocity is close to 2002 meters per second.
03:06
And that's our answer.
03:09
Now for b, we want to find a horizontal distance traveled.
03:14
And to do that, what we can do is write down that the displacement, which we're gonna call d, in the x -axis is equal to the initial velocity in the x -axis, multiply it by the time.
03:30
And we just found the speed of the airplane...