Inertia
Every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force.
Tightening of seat belts in a car when it stops quickly.
Force
The push or pull on an object with mass causes it to change its velocity.
The force of a bat on the ball
Energy an object possesses because of its position in a gravitational field.
A car that is parked at the top of a hill.
The energy an object has because of its motion.
A soaring baseball
The potential energy stored as a result of the deformation of a particular elastic object, or a spring.
A spring hanging vertically from the ceiling, with somebody pulling down on the other end.
The amount of energy transferred or converted per unit time.
A 60-W light bulb, for example, expends 60 J of energy per second