[问答题]
Suppose a car moves at constantqj 9sl(7srr5 6lp)w opax+ (*6jgoobz speed along a hilly road. Where dox o,;lr0xomn. es the car exert the greatest and least forces on the road: (a) at the top of a hill, (b) at a dip lxn0o;.ox,m r between two hills, (c) on a level stretch near the bottom of a hill?
