Force: A push or a pull. Forces are described in terms of both magnitude (how strong) and direction. This means forces are a vector quantity.

Vector: a quantity that has both a magnitude (size) and a direction.

Newton: the metric unit of measure for force is the Newton. One Newton (1N) is equal to a force that causes an object with a mass of 1 kg to accelerate at 1 m/s.

Net Force:

•When you combine or add together all of the forces acting on an object.

•When the net force is greater than zero, the forces acting on the object are unbalanced.

•When the net force is zero, the forces acting on the object are balanced and the object is in equilibrium.

Unbalanced Force: This type of force will cause a change in the motion of an object. It can, for example, cause an object to move, stop, or change direction.

•Unbalanced forces in the same direction: the net force is the sum of the forces that are acting in the same direction.

•Unbalanced forces in the opposite direction: the net force is the difference (subtract) between the two forces

Balanced Force: Equal forces acting on an object in opposite directions are balanced. This type of force will NOT cause a change in the motion of an object.

Equilibrium: This means that all of the forces acting on an object are balanced. Thus, an object that is moving in a straight line at a constant speed will continue to do so and an object that is not moving will continue to remain at rest.

Elastic Force: Matter is considered elastic if an object is able to return to its original shape after being squeezed or stretched.

• Compression: the force that squeezes or pushes matter together. For example, compressing or stretching a spring. • Tension: the force that stretches or pulls matter. For example, pulling on the ends of a rope.

Friction: This is a force that resists motion between two surfaces that are in contact with each other.

•The amount of friction that occurs depends on how rough or smooth each surface is and on how strong the force is pushing the two surfaces together.

•Friction acts in a direction opposite to the direction of the object’s motion.

• Static friction occurs when you first start to move an object that is at rest. You must use enough force to overcome the resistance of the stationary object and to start it in motion.

Stationary object

Hard to get it moving.Must be lots of stuff

for letter writing inside this box.

No. The object isn’t stationery. It’s stationary!

sliding friction occurs when solid surfaces slide over each other. Examples: snowboarding, writing on your paper, applying the brakes in a car.

rolling friction occurs when an object on wheels moves across a surface. Examples: skateboards, bicycles, cars, planes, trains.

Fluid friction occurs when an object moves through a liquid or a gas. Examples: swimming, flying in an airplane, applying oil to the moving parts of a machine so that they can move more easily.