A 66.7-kN car is travelling at 66.5 mph when the driver decides to exit the freeway by going up a ramp. After coasting 418 m along the exit ramp the car\'s speed is 28.9 mph, and it is h = 13.1 m above the freeway. What is the magnitude of the average drag force exerted on the car?

Question

Hint: How is the work done by a non-conservative force such as drag related to the change in the car\'s mechanical energy?

Elena · Answer

mg=66700 N, m=66700/9.8 kg, s= 418 m, v ₀=66.5 mph =29.7 m/s v=28.9 mph=12.9 m/s, h=13.1 m KE1-KE2= W(dr)+ PE m•v₀²/2 - m•v²/2= F(dr) •s +m•g•h Solve for “F(dr)”