Motion

Motion is described by an object's direction and speed.

Friction is a force that opposes motion.

Energy that is being used or simply an object moving.

Energy at rest.

Any push or pull that causes an object to move, stop, or change speed, direction, or shape.

The study of  natural phomena and properties of matter and energy.

When an object is pushed or pulled in opposite directions by two equal forces, the result or net force will be zero.

Net force is the sum of all the forces acting on an object. For example, if two forces are acting upon an object in opposite directions, and one force is greater than the other, the forces can be replaced with a single force that is the difference of the greater and smaller force. That force is the net force.^{For more info go to en.wikipedia.org[1]}  

When equal and opposite forces act upon an object and the resulant or net force is zero, the forces are termed balanced foces.

When unequal forces act upon an object and the resulant  or net force is not equal to zero, the forces are termed unbalanced forces.