Forces Mastery Check

Contact Force

The general type of force in which an object must PHYSICALLY TOUCH another object in order to exert a force on the object.

Non-Contact Force

The general type of force in which an object can exert a force on another object WITHOUT physically touching the object. These forces act at a distance in a force field.

Force

A push or pull that AFFECTS an object MOTION is a

newtons

Forces are labeled and measured in , which is the standard unit of measurement for forces.

both direction and magnitude

Vectors have

normal force

This contact force is the UPWARD acting force perpendicular to the surface with which an objects rests on. This force works against gravity and is responsible for keeping you from falling through your chair.

kinetic friction

This contact force works to slow down objects in motion. This force acts against an applied force and generates heat as two surfaces rub together.

drag (air resistance)

This contact force acts to slow down objects in a fluid (liquid or gas). It's similar to friction but is found in water or air.

spring force

This type of contact force is the force exerted in an elastic object when stretched or compressed. The elastic object will have a tendency to snap back when the force is released.

tension

This contact force works in both directions of a rope, string, wire or cable when pulled tight

Net Force

A combination of all forces on an object

Balanced forces make an object…

stay at rest

Unbalanced forces make an object…

move

Applied Force

A force that is exerted on an object by a person or another object by pushing or pulling.

Non-Contact Force

A force that one object can apply to another object without touching it

This scientist is most famous for his work on the laws of gravity. Some say he made the groundbreaking discovery when he saw an apple fall from a tree.

Sir Isaac Newton

Newton's 1st Law of Motion

An object at rest remains at rest, and an object in motion remains in motion at the same speed and in the same direction unless acted on by an outside force.

Inertia

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

Free Fall Motion

Any motion of an object where the only force being applied to the mass of the object is gravity

Gravity

The attractive force between 2 objects having mass, which PULLS the other object towards it's own center of mass.

This scientist is known for dropping a cannonball and stone from the Tower of Pisa and discovered they strike the ground at practically the same time.

Galileo Galilei

Gravitational Force Field

The region of space surrounding a body in which another body experiences a force of gravitational attraction.

What two factors affect the strength of gravity?

Mass and distance

How does mass affect gravity?

The greater the mass, the greater the gravity.

How does distance affect gravity?

As distance increases, gravity decreases.

What is the acceleration due to gravity on Earth?

9.8 m/s2

Newton's 2nd Law of Motion

Force = mass x acceleration

Mass

The amount of matter in an object.

Weight

A measure of the force of gravity on an object. The weight of an object can vary with the strength of gravity (ex: standing on Earth vs. Jupiter).

electric force

the attraction or repulsion between electric charges

electric field

a region around a charged object where the object's electric force is exerted on other charged objects

static electricity

charges build up on an object, but they do not flow continuously

conservation of charge

The law that states that charges are neither created nor destroyed but only transferred from one material to another.

charge by friction

is the transfer of electrons from one uncharged object to another by rubbing

charge by conduction

is the transfer of electrons from a charged object to another object by direct contact.

charge by induction

is the movement of electrons to one part of an object that is caused by the electric field of a second object.

static discharge

The loss of static electricity as electric charges transfer from one object to another

proton

subatomic particle that has a positive charge and that is found in the nucleus of an atom

neutron

A subatomic particle that has no charge and that is found in the nucleus of an atom

electron

A subatomic particle that has a negative charge

Iron

Steel objects can become temporary magnets because they are mainly composed of which element?

Opposite poles do this

Attract

Like poles do this

Repel

Compass

an instrument that shows the direction of magnetic north

Magnetic Field

The area of magnetic force around a magnet

Magnet

any material that attracts iron and materials that contain iron

Magnetic Poles

two ends of a magnet where the magnetic forces are strongest

Electromagnet

A temporary magnet created by running current through coiled wires. The strength can be increased by increasing the flow of current OR the number of coils.

Magnetic Field Lines

invisible lines that map out the magnetic field around a magnet