Forces are a big part of physics. Physicists devote a lot of time to the study of forces that are
found everywhere in the universe.
The forces could be big, such as the pull of a star on a planet. The forces could also be very small,
such as the pull of a nucleus on an electron. Forces are acting everywhere in the universe at all
times.
If there is more than one force acting on an object, the forces can be added up if they act in the
same direction, or subtracted if they act in opposition