Definition of Forces
Definition: A force is usually described as a vector quantity with a definite magnitude and a definite direction which can be either a push or a pull on an object.
Effects: Forces can have different effects on objects according to the type of material the object is made of.
- the object could change its state of motion (make it move, make it go faster, stop it, or slow it down)
- or it could change the shape of the object (deform it, resize it, reshape it...)
Fundamental Forces: As far as what physicists know today there are only three or may be four fundamental forces
- Force of gravity -- a very weak force
- Strong Nuclear Force -- a very strong force
(it holds the particles that make up the atoms and keeps them together)
-Weak Nuclear Force -- weaker than the strong nuclear force
(it is responsible for the fact that some particles within the atom are released making the atoms radioactive)
-Electromagnetic Force -- a strong force
(made up of the electrostatic force of attraction between two charged particles at rest, and the magnetic
force produced when these particles move)
-Electroweak Force -- a new force
This force is believed to be similar to the electromagnetic force.
Units of Force
The diagram shows a spring scale measuring the force of gravity on a medium-sized apple. Its mass is about 100 g; its force of gravity is 1.0 N.
Another word for force of gravity is WEIGHT! Be Careful not to confuse Mass with Weight.
Although in everyday language they are used to mean the same thing, in Physics we use mass (a scalar quantity) to mean the "amount of matter in an object"; whereas weight is a vector quantity that measures the gravitational pull on an object (i.e. The Force of Gravity on an object).