ForcePhysical Science 12

Basic 5

Force is a push or pull

All forces have a size and direction.A force can change the acceleration of an

object.(size and direction)

Anytime you see a change in an object’s motion, it was probably caused by a force.

All forces act upon an object.

For a push or pull to happen something has to receive it.

You can’t push or pull nothing. But, just because a force acts upon

it does not mean motion occurs.

Force: A push or pull.All forces have a size/amount and

direction.

Newton: The SI unit to express or measure force “N”

Many forces act upon an object before a push or pull occurs the object must

overcome these natural forces. (friction, gravity)

Net Force: is the total combination of all forces acting upon the object.

(Answer to the problem.)

If forces are in the same direction you add the forces.

If forces are in the opposite direction you subtract the forces.

Balanced Forces= 0 NewtonsUnbalanced Forces= When net force is

not 0 Newtons.

When an unbalanced force acts upon an object, the object moves

or accelerates.

When the forces on an object are balanced, the net force is 0, there

is no change in the objects motion.

You cannot always see or feel forces. Gravity, static electricity,

magnetic force

Net force is the total of all the forces acting on an object.

Newton is the SI unit for (N) force

Forces that oppose motion:

Friction stops objects in motion, it opposes/resist motion between two surfaces that are in contact.

2 types of Friction:A. Kinetic: friction between moving surfaces

1. Sliding kinetic friction (greater)2. Rolling Kinetic friction

Easier to move objects on wheels than to slide them across a surface.

Friction occurs because the surface of the object is rough.

2 main factor determine friction1. Force pushing the surfaces

together.2. Roughness of surfaces

(more roughness)

Types of friction:

Kinetic: (moving) Between two objects sliding and rolling.

Static: (not moving) Balance force.

Air Friction: Air resistanceFluid Friction: Water Resistance