(a) How high (in m) a hill can a car coast up (engine disengaged) if friction is negligible and its initial speed is 78.0 km/h? (Enter a number.) m (b) If, in actuality, a 750 kg car with an initial speed of 78.0 km/h is observed to coast up a hill to a height 13.0 m above its starting point, how much thermal energy (in J) was generated by friction? (Enter a number.) J (c) What is the average force of friction (down the slope) if the hill has a slope 2.5 above the horizontal? (Enter your answer in N. Enter a number.) N H