- #1

tucky

- 30

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Thank you for dduardo and HllsofIvy for helping me on my last question. Once again, I am having problems with my physics homework. Here is my question:

In an amusement park ride, people in a car are dropped some horrible distance, screaming for their lives. The car rounds a curved track and is brought to a halt be a braking force on a horizontal piece of track. The car a=gas a mass if 1100kg. Point A is 50m off the ground. Point B is 20m off the ground. And point C is 5m off the ground. The track is frictionless until you get to the horizontal braking section. The braking force is 2500lb. 1.) Find the velocity of the car at B and when it reaches the horizontal track. 2.)How far will the car move on the horizontal track? 3.)Then re-work the problem with the braking force kicking in at point B rather than at the horizontal track.

Here is my work, which is more than likely wrong because I have no ideal how what a breaking force is or how to calculate that into my problem:

W = m * g * y

W = 1100kg * 9.8 N * 30 m = 323,400J

W = F * d

323,400J/30m= 10780kg (m/s^2)

a = F/m = 10780kg m/s^2 /1100kg =9.8 m/s^2

v^2=v0^2 +2 average acceleration (x – x0 )

v^2 =0 + 2 (9.8 m/s^2) (30m-0m)

square root of v^2 = square root of (508 m/s)^2

1.) Therefore the velocity at B= 22.5 m/s

W = mv^2 /2 = 1100kg(22.5m/s)^2 /2 = 278,437.5J

2.) W = m * a * d = 278,437.5J * 9.8m/s^2 * d = 25.83m was the distance

3.) I have no ideal how to work the third part.