Mass, Force and Motion:

Mass:

The word mass, as used by physicists, refers to amount of matter in terms of its ability to resist motion whenever acted on by a force. A good synonym for mass is heft. Each material object has a particular, definable mass. The Sun has a certain mass; Earth has a much lesser mass. A lead shot has a far lesser mass still. Even subatomic particles, like protons and neutrons, have mass. The visible-light particles, termed as photons, act in few ways as if they have mass. A ray of light places pressure on any surface it strikes. The pressure is tiny, though it exists and at times can be measured.

Force:

Visualize that you are in a spacecraft orbiting the Earth; therefore everything in the cabin is weightless. The two objects float in front of you: a brick and a marble. You know that the brick is extra massive than the marble. Though, either the brick or the marble can be made to move across the cabin when you give it a push.

Assume that you flick your finger against the marble. It flies across the cabin & bounces off the wall. Then you flick your finger merely as hard against the brick. The brick takes numerous minutes to float across the cabin and bump into the opposite wall. The flick of your finger imparts a force to the marble or the brick for a moment, though that force has a different effect on the brick than on the marble.