A 7780 ‑kg car is travelling at 30.7 m/s when the driver decides to exit the freeway by going up a ramp. After coasting 404 m along the exit ramp, the car's speed is 13.3 m/s, and it is h = 13.1 m above the freeway. What is the magnitude of the average drag force F drag exerted on the car?

Question

Jesse Durham

Physics

4 April, 18:41

A 7780 ‑kg car is travelling at 30.7 m/s when the driver decides to exit the freeway by going up a ramp. After coasting 404 m along the exit ramp, the car's speed is 13.3 m/s, and it is h = 13.1 m above the freeway. What is the magnitude of the average drag force F drag exerted on the car?

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Answers (1)

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Jace Guerra · Answer 1

4899.47 N

Explanation:

mass of the car = 7780 kg, u, initial speed = 30.7 m/s, v, final speed = 13.3 m/s

d = 404 m and h = 13.1 m

initial kinetic energy of the car = potential energy attained by the car climbing the ramp + the work done by friction against the motion + final kinetic energy

1/2 mu² = mgh + (F * d) + 1/2mv²

3666286.1 J = 998796.4 J + (404 F) + 688102.1 J

404 F = 3666286.1 J - 998796.4 J - 688102.1 J

F = 1979387.6 / 404 = 4899.47 N