Question

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 h=−3t'2+0t+48. How long will it take the rocket to hit the ground?

Answer 1

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

`h=-3t^2+0t+48`

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

`\begin{gathered} -3t^2+0t+48=0 \\ t^2=(48)/(3) \\ t^2=16 \end{gathered}`

which gives

`t=\pm4`

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

Final Answer: t=4 seconds.