Rocket Out of Fuel: Time and Altitude

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The discussion revolves around a physics problem involving a rocket that accelerates upward at 4.0 m/s² until it runs out of fuel at 1500 meters. The initial calculations indicate that the rocket reaches a velocity of 110 m/s when it exhausts its fuel. Participants are seeking assistance on determining the time taken to reach this altitude, the maximum altitude achieved, the total time in the air, and the velocity upon impact with the Earth. There is confusion regarding the application of the equations of motion and the need for clarity on units. The conversation highlights the importance of correctly applying kinematic equations to solve the problem effectively.
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Homework Statement



A rocket rises vertically, from rest, with an acceleration of 4.0 until it runs out of fuel at an altitude of 1500 . After this point, its acceleration is that of gravity, downward.
How long does it take to reach this point?

What maximum altitude does the rocket reach?

How much time (total) does it take to reach maximum altitude?
With what velocity does the rocket strike the Earth
How long (total) is it in the air?

Homework Equations



x=x+vt+.5at^2

The Attempt at a Solution



I found velocity when it runs out of fuel to be 110m/s don't know how to get the rest??
 
Physics news on Phys.org
We need more units! I'm guessing acceleration of 4.0m/s and an altitude of 1500 meters?
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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