Mass is how much 'stuff' is in something. Mass is something that all objects have, which means if an object is moving, it has momentum. The amount of momentum that something has changes depending on two different things: how much stuff is moving, and how fast that stuff it going!
For example, if a big dump truck is rolling down a hill, and a little car is rolling down the same hill, the big truck would go faster because it is bigger, so it has more mass, which gives it more momentum.
Here is a game link. http://armorgames.com/play/4702/momentum-masterAnd a quick little quiz: http://www.physics4kids.com/extras/quiz_motion_momentum/q02_no.html
For example, if a big dump truck is rolling down a hill, and a little car is rolling down the same hill, the big truck would go faster because it is bigger, so it has more mass, which gives it more momentum.
Here is a game link. http://armorgames.com/play/4702/momentum-masterAnd a quick little quiz: http://www.physics4kids.com/extras/quiz_motion_momentum/q02_no.html
In the video below, the cat has more mass then the spinning part of the chair does, so when she jumps on to the chair her momentum causes the chair to spin around.
The video below has audio.