- #1

TheRedDevil18

- 408

- 1

## Homework Statement

**Please check my work**

A model rocket is launched vertically upwards with an initial speed of 50m/s. It accelerates with a constant upward acceleartion of 2m/s until its engine stop at an altitude of 150m.

2.4.1) What is the maximum height reached by the rocket?

2.4.2) How long after lift-off does the rocket reach maximum height?

2.4.3) How long is the rocket in the air?

## Homework Equations

equations of motion

## The Attempt at a Solution

2.4.1) To get the max height I first found the final velocity of the rocket before the engine was switched off. I got this to be 55.68m/s. I then used this to find the height reached after the engine was switched off by making it the initial velocity and using the acceleration of 9.8m/s. I got this to be 158.18m. So the max height is 308.18m.

2.4.2) By breaking the problem into two parts(one 150m and the other 158.18m)I got the times to be 2.84s and 5.68s. Adding them up gives me 8.52s to reach its max height.

2.4.3) Multiplied the time by two(going up and coming down) to get 17.04s.

Please could someone check my work, any help would be greatly appreciated