Pytels Dynamics 12.39: A rocket is launched vertically

[Alexanddros81]

Homework Statement

A 2000-kg is launched vertically from the surface of the earth. The engine shuts off after providing a constant propulsive force of 60 kN for the first 20 seconds. Neglect the reduction in the mass of the rocket due to the burning of the fuel and the variation of the gravitational acceleration with altitude. Calculate the altitude of the rocket at the end of the powered portion of the flight.

Homework Equations

The Attempt at a Solution

I have tried applying Newton's second law ΣFy=ma => F-W=ma (1)
Then I found right hand a of eq (1) and done the integration to find v and x.

Is this the right way to go?

 

[TSny]

Sounds like a good plan.

 

[Alexanddros81]

Is this correct?

 

[TSny]

Is this correct?

Yes. Nice work!