ForcesPages 188 to 191

Forces• Force - a push or a pull, measured in

Newtons (N)• Contact Force – is a push or a pull one

object applies to another object that is touching it. Example : Friction

• Noncontact Force – a force that one object applies to another object without touching. Example : Gravity

Forces• Gravity – is an attractive force that

exists between all objects that have mass

The strength of the force depends on the mass of each object and the distance between them• Mass – the amount of matter in an

object• Weight – how strong gravity pulls on

an object’s mass

Forces• Friction - is a contact force that resists

the motion of two surfaces that are touching. Stops motion

• Air resistance – is the frictional force between air and objects moving through it.

Forces

• Balanced forces• Equal strength, but

going in opposite directions.

• Do NOT cause movement

• Unbalanced forces• Will cause the object to

move in the direction of the combined force