Replies

Are you honestly trying to tell me that the work done per unit time of a rocket increases with its velocity?

I most certainly am.

If you had taken high-school physics, you would know that "work" is "force exerted over a distance".

If you push very hard on a very big rock, moving it not at all, you have done no work, no matter how tired you are at the end.

"Power" is the rate of doing work.

If you increase the rate of distance covered (higher speed), you increase the rate of work and hence the power.

Slightly altering the numbers of my previous example, a rocket with 550 pounds of thrust, tethered to remain stationary, does no work. That same rocket moving at one foot per second does 550 foot-pounds of work per second, for one horsepower. That rocket at 36000 feet per second (roughly escape velocity from Earth) has the equivalent of 36000 horsepower.

If you had taken high-school physics, you would know that "work" is "force exerted over a distance".

Considering that I am finishing my BS in physics and previously was a reactor operator on a submarine nuclear reactor, I think I have the energy, force, and power ideas covered. Thanks.

I am telling you that you are wrong about the constant force. You are not listening. It is closer to a constant power that is applied and the force applied drops off over time.

Power is the amount of work done per unit time. Let me repeat, this work does not come from nowhere. It isn't magic. You use fuel and chemical reactions. If you are going to exponentially increase the amount of power of your rocket then you are going to have to exponentially increase the size of the support systems in your rocket (i.e. the size of the combustion chamber, the piping for the fuel, the cooling tubes, etc).

Here is a graph of the solid rocket boosters on the Space Shuttle. They separate at 126 seconds (where the graph ends). The initial spikes are caused by mass loss and atmospheric interference. After about 80 seconds (and finally above most atmospheric interference) the profile is clear. Thrust is not even close to constant nor is it trying to be.