A model rocket is launched straight upward with an initial speed of 50.0 m/s. It accelerates with a constant upward acceleration of 2.00 m/s2 until its engines stop at an altitude of 150 m. (a) What can you say about the motion of the rocket after its engines stop? (b) What is the maximum height reached by the rocket? (c) How long after liftoff does the rocket reach its maximum height? (d) How long is the rocket in the air?

Question

A model rocket is launched straight upward with an initial speed of 50.0 m/s.  It accelerates with a constant upward acceleration of 2.00 m/s2 until its engines stop at an altitude of 150 m.  (a)  What can you say about the motion of the rocket after its engines stop?  (b)  What is the maximum height reached by the rocket?  (c)  How long after liftoff does the rocket reach its maximum height?  (d)  How long is the rocket in the air?

anonymous · Answer

You can start by determining the time at engine cutoff. Here you know it stops at 150m and the acceleration is constant (makes it easy). 

$$x = x _{0} + v_{0}t + 0.5at^2$$

Here, we want to find the time where x = 150. Presuming it was launched from the ground, x0 = 0. We know velocity and acceleration. We can solve for t.

anonymous · Answer

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