Types of Forces. What is a force? A push or a pull.

Types of

Forces

What is a force?

A push or a pull

Push

Pull

How do we measure force?

The unit used to measure force is the Newton (N)

Direction of the forceThe direction of a force is the direction of the push or pull.

In what direction is the push or pull below?

Combining Forces

• When more than one force acts on an object, the forces combine.

• The combination of all the forces on an object is called the net force.

How do forces in the same direction combine?

ADD the forces together to form net force.

What is the net force below? 10 N

How do forces in opposite direction combine?

SUBTRACT: larger force minus the smaller force

What is the net force below? In what direction will the object move?

Larger force - smaller force 6 N - 3 N

= 3 N

To the left3 N

What is inertia?

The tendency of an object to resist a change in its motion.

Mythbusters: Tablecloth Inertia

The more mass an object has, the greater its inertia.

Which is harder to push??

Wear seat belts!

Because of inertia, objects (including you) resist changes in their motion. When the car going 80 km/hour is stopped by the brick wall, your body keeps moving at 80 km/hour.

Don’t let this be YOU!

Contact Force

A force exerted only when two objects are touching each other.

Friction Air Resistance Buoyant force Tension Compression

Non-contact Force

A force exerted by one object on another object when the objects are not Touching

Gravity Electrical force Magnetic force

Friction

A force that opposes the motion of two surfaces in contact.

• Smoother surfaces = less friction• Rougher surface = more friction

OR

OR

Air Resistance

Force exerted by air on objects moving through the air.

Buoyant Force

The upward force that keeps things floating.

Tension

A pulling force

Blast from school’s past!

Tension is the force that pulls two tectonic plates apart!!

Compression

Force that pushes objects together

Gravity

A pull that every object exerts on another object due to its mass.

Electrical Force

Charged objects repelling or attracting each other.

+ + = repel + - = attract