Forces

1.
- A Force is a pull or a push.

2. Examples:
- Friction:
Friction is a force which acts when two objects are rubed together. It acts to the opasite direction to movement. Friction causes objects to heat up and also causes their surfaces to wear away.
- Gravity:
Every object in the Universe attracts every other object in the universe. This invisible force for masses to move toward each other is called Gravity.
When you weight yourself, your weight may be around 30kg to maybe 50kg because of Gravity. Your weight is the result from the product of the force of gravity and the mass of you.Why two masses separated in space have a gravitational attraction to one another remains unknown, despite much research and various theories. These theories are listed on the left.
-Magnetic:
The force exerted between magnetic poles, creating magnetization is known as magnetic force. Every magnet has a north and south pole, just like the earth.Opposite poles attract so the north pole attracts the south pole and the south pole attracts the north pole. Like poles will repel (push away from) each other - so if you place two north poles together or two south poles together they will push each other away. A magnet's strength is strongest at the poles and weakest in the middle. The space around a magnet is called a magnetic field. It is this invisible area where the force of a magnet can be felt. For example, the closer you bring a paper clip to a magnet, the more you will feel the pull of the magnetic field. Just like what you did earlier.
- Nuclear Force:
The protons in the nucleus of an atom are positively charged. If protons interact, they are usually pushed apart by the electromagnetic force. (Remember, opposite charges attract, but like charges repel!). However, when two or more nuclei come VERY close together, the nuclear force comes into play. The nuclear force is a hundred times stronger than the electromagnetic force so the nuclear force may be able to "glue" the nuclei together so fusion can happen. The nuclear force is also known as the strong force. This is one of the four fundamental forces in the Universe. The nuclear force keeps together the most basic of elementary particles, the quarks. Quarks combine together to form the protons and neutrons in the atomic nucleus.

3. The units of force:
- Newtons, Dynes, kilogram-force(kilopond), pound-force, poundal.
More information on Units of Forces.

4. Equation of Force:
- Mass x Acceleration = Force.