That a body in motion persists in maintaining its direction unless other forces intervene.

That the gyroscope overcomes the force of gravity while rapidly revolving.

That a body set in motion tends to move in a straight line.

That the centre of gravity must be maintained by balance if disturbed or shifted.

That force is the cause of a change in the velocity or direction of motion of a body.

That all alterations of velocity take place gradually and continuously.

That centripetal force and centrifugal force are force directed by radial action.

That the air offers resistance, which increases when the air is in motion.

That friction offers resistance to power.

That the smaller the surface presented, the less friction there is to resist.