A toy rocket is launched from a 3m

platform, at 8.1 m/s. The height of the
rocket is modelled by the equation
h= -4.9t^2 + 8.1t + 3, where h is the
height, in metres, above the ground
and t is the time, in seconds.
1. After how many seconds will the
rocket rise to a height of 6 m above
the ground? Round your answer to
the nearest hundredth.
2. When does the rocket fall again to a
height of 6 m above the ground?
3. Use your answers from parts a) and b)
to determine when the rocket reached
its maximum height above the ground.

1 answer

plug in 6 for h

use the quadratic formula to find the two answers
... one going up , the other coming down

the average of the two is the time for max height