A cylindrical can has height h and radius r both measured in cm. If the rate of increase of volume of the can with respect to height equals the rate of increase of volume with respect to radius, what is the relationship between height and radius

Ablue car pulls away from a red stop-light just after it has turned green with a constant acceleration of 0.5 m/s 2 . a green car arrives at the position of the stop-light 6.5 s after the light had turned green. if t = 0 when the light turns green, at what time does the green car catch the blue car if the green car maintains the slowest constant speed necessary to catch up to the blue car? answer in units of s.