Pytels Dynamics 12.39: A rocket is launched vertically

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Homework Help Overview

The problem involves the dynamics of a rocket launched vertically, focusing on the forces acting on it during the powered flight phase. It specifically examines the application of Newton's second law in calculating the altitude reached after a specified time under constant thrust.

Discussion Character

  • Exploratory, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to apply Newton's second law to analyze the forces on the rocket and integrate to find velocity and altitude. Some participants express support for this approach, while others seek confirmation of its correctness.

Discussion Status

The discussion includes affirmations of the original poster's approach, with some participants indicating that the reasoning appears sound. However, there is no explicit consensus on the correctness of the calculations or the method used.

Contextual Notes

Participants are working under the constraints of neglecting fuel mass reduction and variations in gravitational acceleration, which are assumptions that may influence the analysis.

Alexanddros81
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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?
 
Physics news on Phys.org
Sounds like a good plan.
 
Pytel_Dynamics040.jpg
Is this correct?
 
Alexanddros81 said:
Is this correct?
Yes. Nice work!
 

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