(a) How high a hill can a car coast up (engine disengaged) if work done by friction is negligible and its initial speed is 110 km/h? (b) If, in actuality, a 750-kg car with an initial speed of 110 km/h is observed to coast up a hill to a height 22.0 m above its starting point, how much thermal energy was generated by friction? (c) What is the average force of friction if the hill has a slope 2.5º above the horizontal?
Step-by-step solution Step 1 of 7 At the maximum height, the kinetic energy of the car is converted into potential energy. Therefore, Here is the mass of the car, is the maximum height attained by the car, is the initial speed of the car. Step 2 of 7 (a) Use the above formula, s (3) Step 3 of 7 Substitute for and for . Therefore, the maximum height attained by the car is . Step 4 of 7 (b) Since coasts only to 22 m, some of the energy must be lost to thermal energy due to friction . Therefore,