A catapult launches a test rocket vertically upward from a well, giving the rocket an initial speed of 79.8 m/s at ground level. The engines then fire, and the rocket accelerates upward at 3.90 m/s2 until it reaches an altitude of 1150 m. At that point its engines fail, and the rocket goes into free fall, with an acceleration of −9.80 m/s2. (You will need to consider the motion while the engine is operating and the free-fall motion separately.)

Question

anonymous · Answer

I got t=11.294 s but webassign is telling me I'm wrong.

anonymous · Answer

What do u have to calculate actually?

ash2326 · Answer

11.294 s is the time taken for the first part of the journey.
If you need to find the total time, then you need to find the time for the second part also. A body freely falling under gravity from a height of 1150 meters, find the time and add it to the time you have already found.