A test rocket is fired vertically upward from a well. A catapult gives it an initial velocity of 79.5 m/s at ground level. Subsequently, its engines fire and it accelerates upward at 4.10 until it reaches an altitude of 920 m. At that point its engines fail, and the rocket goes into free fall, by an acceleration of -9.80
1) What is its maximum altitude?
2) How long is the rocket in motion above the ground?
3) What is its velocity now before it collides with the Earth?