A force is any push or ____________.

Force is measured in the unit _____________

http://www.brainpop.com/science/motionsforcesandtime/force/

Review

2 groups of forces CONTACT FORCES

Examples:FrictionNormalApplies

FORCES ACTING FROM A DISTANCE

Examples”ElectricalMagneticGravity

a force that is applied (by contact) to an object by a person or another object

Examples) pushing open a doorlifting weights

throwing a ball moving a box

Applied Force

The force of one object or surface rubbing against another. It opposes motion.

STATIC: Stays stillKINETIC: Moving

(Examples) snowboarding car driving on the road lab table against the floor

Friction

Surfaces touching

Pressure of objects

2 factors that effect Friction

Effects of friction Objects slow down Objects heat up

the support force exerted upon an object that is in contact with another stable (still) object

Examples) book on a table standing on the ground leaning against the wall

Normal Force

The force of charges (positive and negative) that react with each other

-The closer together the particles are, the stronger the force they create

Example) lightening in picture above

Electrical Force

The force that pulls objects towards each other

Weight is the force of gravity on an object

Any object with mass (matter) has gravity=

The Law of Universal Gravitation

Gravitational Force

2 things affect gravity Mass Distance between

objects

Magnetic poles attracting or repelling

Magnetic Force

Tension: force that is transmitted through a string, rope, cable or wire when it is pulled tight by forces acting from opposite ends

Some other forces:

Spring Force: the force exerted by a compressed or stretched spring upon any object that is attached to it

Some other forces:

When the forces are ______________, they cause an object to speed up, slow down, or change direction.

The overall amount of forces acting on an object is a _________ force.

If the forces are acting in the same way then add them

Boy= 20 N Girl =20N20 + 20 = 40 N

If the forces are opposite, subtract them.