1. Forces : -A force is a push or pull -It is the capacity to do work or cause physical change. -The SI unit of force is the newton (N) -Force can be measured with force-meters.Spring balances are force-meters.
2. Pressure
2.1. -Pressure is the force per unit area. -Pressure increases when force increases or area decreases.
3. Force :
3.1. Frictional Force
3.1.1. -Friction slows down and stops a moving object.
3.1.2. -Friction produces heat.
3.1.3. Disadvantage : Frictions causes objects to wear out. examples :
3.1.3.1. Walking: If there is no friction between your shoes and the floor, you would be slipping in one place forever.
3.1.3.2. Breaks: Frictional force is used to stop your car/bicycle from moving when you step on the breaks.
3.2. Gravitational Force
3.2.1. Acts towards the center of mass of an object
3.2.2. Gravity exists between any two objects
3.2.3. The force of gravity pulling down on an object is called its weight.
3.2.4. Examples : -Tides -(Shooting a basketball: The force of gravity acts on the ball and pulls it back to the floor.)
3.3. Magnetic Force
3.3.1. A magnet exerts a magnetic force.
3.3.2. A magnet can attract objects made of magnetic material such as iron or steel.
3.3.3. A magnet can exert a force on other magnets