Figure 5.43 Exercise 5.8.
5.9 At a certain part of your drive from home to school, your car
(mass 1600 kg) will coast in neutral at a constant speed of 72 km/h
if there is no wind. Examination of a topographical map shows that
for this stretch of straight highway the elevation decreases 200 m
for each 6000 m of road. What is the total resistive force (friction
plus air resistance) that acts on your car when it is traveling at
72 km/hr.