Forces

Force

Push or pull that acts on an object

Newton

The measurement of force

*You can measure force using the spring scale at a grocery store.*A force is measured in newtons.*one newton is equal to one kilogram meter per second squared

This picture is an example of the definition of force.

Net Force

Overall force acting on an object after all forces are combined

Friction

A force that opposes the motion of objects that that touch as they move past each other

*You can us an arrow to represent the direction and strength of a force.*Sometimes the net force acting upon an object is zero when the forces are equal.

This Picture is an example of unbalanced forces.

Static Friction The friction force that acts on

objects that are not moving

Sliding Friction A force that opposes the

direction or the motion of an object

*Examples of balanced forces are very common*Often the forces on an object are unbalanced.

The man is doing work by pushing the block and the result Is the block moving

Rolling Friction The friction force that acts on an

rolling object

Fluid Friction Opposes the motion of an object

through a fluid

*Gravity is an attractive force that is a natural part of the earth .*Momentum doesn’t increase or decrease.

This is the formula to find the amount offorce acting upon an object.

Air Resistance

Fluid friction acting on an object in air

Terminal Velocity Constant velocity of a falling

object when the force of air resistance equals the force of gravity.

*Gravity is the weakest universal force.*Gravity is the most efficient force at a long distance.

The lawnmower is experiencing rolling friction because its wheels are rolling on the ground.

Projectile Motion

The motion of a falling object after it is given an initial forward velocity

Gravity

Force that acts on any of wo masses

*Conservation means that something has a constant value.*Only when equal and opposite forces act on the same object do they result in a net force of zero

This is an example of gravity because the apple is falling towards the center of the earthFrom the tree.

Inertia The tendency of an object to

resist a change in its motion

Weight The force of gravity acting on an

object

*Different types of friction act on moving and non-moving objects.*Sliding Friction acts to oppose the direction of motion.

The cat will fall when the car stops because there is not enough force to keep it sitting in the dashboard.

The stone launched forward because the driver stepped on the brakes too hard and caused inertia to come into play.

Mass Measure of inertia an object and

depends on the amount of matter in the object

Momentum Product of an objects mass and

velocity

*When an object rolls across the floor both the object and the floor are very slightly bent out of shape.*Friction acts on submarines moving through water and airplanes moving through air.

This is another example of an unbalanced force because the other object tied to the rope has more force then the man.

Law of Conservation of Momentum

If no net force acts on a system then the total momentum of the system does not change

Acceleration

The rate at which velocity changes

*The force of gravity does not require contact with objects to be able to act on them.*Air resistance and gravity are the only forces acting on a projectile.

This picture shows the car accelerating because the wheels are moving faster and faster over time.

Velocity Speed and direction an object is

moving

Instantaneous Speed Rate at which an object is

moving at any given time

*As objects fall to the ground they accelerate and gain speed.*An unbalanced force is a result of forces that are acting on an object not being equal to each other.

This cheetah is moving Very fast and has a highVelocity.

The balls mass and weight forms its momentum, which carries through the other balls to make the ball on the opposite end move.

Constant Acceleration A steady change in velocity

Strong Nuclear Force Powerful force of attraction that

acts only on the neutrons and protons in the nucleus

*You can replace sliding friction with rolling friction.*Weight does not have an effect in how fast an object falls if both of the objects are the same type of object.

The initial forward velocity of the objectSlows as it falls to the ground.

Birds and airplanes face fluid friction in the air the same way submarined face fluid friction in the water.

Centripetal Force Center directed force that

continuously changes the direction of an object to make it move in a circle

Gravitational Force Is an attractive force that acts

between any two masses

*When you push on something you are using force.*Air resistance is the result of fluid friction in the air.

The object has it’s force located In it’s center, making it a centripetalForce.