# Physics

posted by .

Question: A car is on a ramp 100m from the bottom of the ramp (angle of incline=30 degrees):

a. If the potential energy of the car is 80902 J, how much does the car weigh?

b. What is the KE half way down the ramp?

c. What speed is the car moving at the bottom of the ramp?

Please indicate which equation you use, what variable corresponds to each number, and how you got the number that goes with the variable.

Thanks!

• Physics -

a. h = 100sin30 = 50m.

PE = mgh = 80,902J,
m*9.8*50 = 80,902,
m = 165.1kg.

F = mg = 165.1kg * 9.8N/kg = 1618N =
Wt. of car in Newtons.

Wt. = 165.1kg / 0.454kg/lb = 364lbs =
Weight of car in lbs.

b. h = (100/2)sin30 = 25m.
V^2 = Vo^2 + 2gd,
V^2 = 0 + 2*9.8*25 = 490,
V = 22.1m/s.
KE = 0.5mV^2 = 0.5 * 165.1 * (22.1)^2 =
40,318J.

c. V^2 = Vo^2 + 2gd,
V^2 = 0 + 2*9.8*50 = 980,
V = 31.3m/s.

## Similar Questions

1. ### Physics

A car sits in an entrance ramp to a freeway, waiting for a break in the traffic. The driver sees a small gap between a van and an 18-wheel truck and accelerates with constant acceleration along the ramp and onto the freeway. The car …
2. ### physics

The driver of a 1,450kg car, whose iron brake calipers mass is 3kg endures a brain malfuction at the top of a 20 degree parking ramp 20 meters long. It approaches the ramp going 20m/s and the driver recovers just as the car reaches …
3. ### physics

A car accelerates at a constant rate of 3.42 m/s2 from rest at the beginning of a freeway entrance ramp. At the end of the ramp the car has a speed of 25.49 m/s. How long is the ramp?
4. ### Physics

A car with engine trouble slides 85 meters up along a 14 degrees ramp before coming to a stop. If the coefficient of friction between the tires and the road is 0.9, what was the velocity of the car at the bottom of the ramp?
5. ### Physics

A car with engine trouble slides 85 meters up along a 14 degree ramp before coming to a stop. If the coefficient of friction between the tires and the road is 0.9, what was the velocity of the car at the bottom of the ramp?
6. ### physics

A car sits in an entrance ramp to a freeway, waiting for a break in the traffic. The driver sees a small gap between a van and an 18-wheel truck and accelerates with constant acceleration along the ramp and onto the freeway. The car …
7. ### physics

a car rolls down a ramp 4m long that has angle of incline equal to 37 degrees. If the car starts from rest, what will be its velocity at the bottom of the ramp?
8. ### Physics

A 0.2kg toy car rolls down a ramp with a height of 0.7m. What is the speed of the car at the bottom of the ramp. At the bottom it hits a stationary car with a mass of .4 kg. The two cars have velcro bumpers and stick together. At what …
9. ### Physics

You set up a ramp with a length of 1.15 m, raising one end to a height of 0.4 m. You then roll a 0.300 kg toy car down the ramp, starting at rest a)What is the change in potential energy of the toy car rolling down this ramp?
10. ### Physics

A 1400 kg car travels up a 20 degrees incline. The car exerts a constant force of 30,000 N across 100m. The car starts from rest at the bottom of the incline. The car takes 10 minutes to do this. How much work is done by the car?

More Similar Questions