Given: A small toy rocket is launched from a 48-foot pad. The height ( h, in feet) of the rocket t seconds after taking off is given by the formula

Required: To find out how long will it take the rocket to hit the ground.
Explanation: When the rocket hits the ground its height h=0. Hence

which gives

Since time can't be negative. Hence t=4 seconds.
Final Answer: t=4 seconds.