I never thought of this before but when an $8^{th}$ standard student asked me to explain what momentum is, I simply said that it the amount of motion contained in a body and tried to explain that how a truck moving at $10\ \mathrm{m\ s^{-1}}$ has more motion than a cat with the same speed (if you don't believe that such a definition even exists then look here ). But he asked that what's the difference between the speed or velocity and motion, if any? I think there must be some slight difference in how we define these. I particularly know of speed and velocity though not motion. (For me it seems that speed rather than being a different quantity is itself a quantifier of motion and hence am a bit jumbled up)
So if possible can someone clarify:
- What motion is?
And in due process contrast it with other quantities such as speed, etc.