At a very basic level, a force is just a push or a pull.
It can be measured in terms of either of two effects. A force can either change the size and
shape of an object, such as a spring, or change the speed or direction of an object.
One type of force is friction; it is the force that has an effect on the speed of an object,
but not the direction. Frictional force acts to slow down an object in the direction they are
moving. It takes more force to move an object from when it is stopped than to keep it moving
when it is in motion. When an object is stopped, as more force is applied, the more friction is
there until the limiting static frictional force has been reached.
Magnetism is a force which is the force that attracts or drams in an object. Magnetic
force conducts an electrical charge while moving in magnetic fields. The magnitude of the
magnetic force is proportional to the electrical charge, to the velocity, to the magnetic field,
and depends on the directions of the vectors.
The force of gravity is the force of attraction
between all objects that tends to pull them toward one another. It is a force affecting the
largest and smallest objects. This force controls the movement of heavenly bodies; it keeps the
moon in orbit around the earth and keeps the earth and the other planets of the solar system
in orbit around the sun. In outer space, it controls the movement of stars and slows the outward
expansion of the entire universe because of the attraction or gravitational pull of galaxies to
other galaxies.