A cylindrical barrel with a diameter of 6 meters contains collected rainwater, as shown in the figure above. The
water drains out through a valve (not shown) at the bottom of the barrel. The rate of change of the heighth of
the water in the barrel with respect to timer is modeled by
-Vh, where h is measured in meters and
t is measured in seconds. (The volume V of a cylinder with radiusr and height is V xrh.)