# Tag Info

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• 24.8k

### Energy to momentum

There is such a thing as a Photon Rocket or Photon Drive. This takes advantage of the fact that photons have momentum. However, you are not going to get a lot of thrust out of one.
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• 50.8k

### Is it possible to move without throwing or pushing another object or energy?

Classically, the short answer is no as you've expressly asked to ignore the most obvious solution, an object moving at uniform velocity. This means the object must at some point accelerate (otherwise ...
Accepted

• 25.7k
1 vote

### (Why) Is orbital angular momentum conserved for point masses?

Angular momentum(and torque) does not necessarily mean that there are rotations in place. you can define angular momentum for straight lines, however, that isn't very useful to solve any problem. If ...
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1 vote

### Can conservation of angular momentum be proven?

You write our linear velocity $v$ was constant according to our first claim where the “first claim” was The linear velocity is related to it by the equation $𝑣=𝑟𝜔$ But $v=r\omega$ is a scalar ...
• 70.1k
1 vote

### Energy to momentum

You're right, the only way to change linear motion in space is by throwing stuff out, and why is that a problem? Instead consider, most obviously, a nuclear submarine which any number of people think ...
1 vote

### Energy to momentum

The most direct method is to use the Earth's magnetic field. It is generally used only for attitude control (i.e. generating angular momentum), but nothing (except the low efficiency, of course) stops ...
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