2. A car is travelling at 50ft/sec and the engine shuts off. After 10 seconds the car is travelling at 25ft/sec. Suppose that the resistance is proportional to the velocity so that $\frac{dv}{dt} = -\rho v$, $\rho > 0$. Find the velocity of the car, $v(t)$, and the distance travelled, $x(t)$, $t$ seconds after the engine shuts off.
3. Solve problem number 2 where $\frac{dv}{dt} = -\rho v^2$, $\rho > 0$.