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 Question Momentum ( Physics Help and Math Help - Physics Forums Introductory Physics )Updated: 2008-03-12 20:15:20 (9)
 Momentum 1. What is the basic SI unites for momentum and impulse? 2. Know whether impulse and momentum are vector or scalar quantities. 3. What does it mean for a system to be isolated? 4. Differentiate between external and internal forces. 5. Differentiate between elastic and inelastic collisions. 6. Know which type of inelastic collision produces the greatest loss of kinetic energy. 7. Know what happens to kinetic energy in an inelastic collision. 8. Understand and apply Newton's Third Law of Motion. I am having a little difficulty understanding these stuff. Can anyone help a little bit? Thanks, J.
 Answers: Momentum ( Physics Help and Math Help - Physics Forums Introductory Physics )
Momentum

 Originally Posted by JWHooper Well, I remembered my physics teacher was talking about the space relating with the rocket motion. I believe that the answer is b. ... gravity is absent in space. Although the planets have gravity, the empty space universe has zero gravity.
you are wrong frnd....

It is a common misconception that rockets are unable to accelerate in space. The fact is that rockets do accelerate. There is indeed nothing for rockets to push off of in space - at least nothing which is external to the rocket. But that's no problem for rockets. Rockets are able to accelerate due to the fact that they burn fuel and push the exhaust gases in a direction opposite the direction which they wish to accelerate.

i sggest you go through the law from your textbook once again..

physixguru

 Momentum Well, I remembered my physics teacher was talking about the space relating with the rocket motion. I believe that the answer is b. ... gravity is absent in space. Although the planets have gravity, the empty space universe has zero gravity. JWHooper
 Momentum JWHooper, I would advise loking up the definition of a scalar and vector quantities and then doing the same for momentum and impulse, that should clear that question up. Are you working from a textbook? _Mayday_