Algebra 2 question read descripition

Question

A model rocket is launched with an initial velocity of 160 ft/s. The height, h, in feet, of the rocket t seconds after the launch is given by h = −16t² + 160t.

 How many seconds after launch will the rocket be 320 ft above the ground? What is the smaller and larger value? Round to the nearest hundredth of a second.

Answer 1

Using this equation, you want to find the time when h=320 ft. Plug this value in for h.

320 = −16t² + 160t Subtract 329 from both sides of the equation

0 = −16t² + 160t - 320 Simplify by dividing by -16

0 = t² - 10t + 20 Solve using the quadratic equation

t=7.24 and 2.76 seconds