# Science Vocabulary

## Motion

The action or process of moving or being moved.

## Mass

A coherent, typically large body of matter with no definite shape.

## Force

Strength or energy of physical action or movement.

## Balanced Forces

Equal forces acting on an object in opposite directions.

## Unbalanced Forces

An equal force acting on an object causing it to move in one direction.

## Work

Force exerted on an object that causes it to move.

## Speed

Distance travelled per unit time.

## Distance

The amount of space between two things or people or the length of a race.

## Time

The amount of time that is left, has past, or currently is.

## Velocity

A variable that tells you both speed and direction.

## Acceleration

Change in velocity divided by the time it takes for the change to occur.

## Deceleration

A decrease in speed.

## Energy

Capacity to do work.

## Newton's Law of Inertia

An object in motion (or at rest) will tend to stay in motion (or at rest) until it is acted upon by an outside force.

## Newton's Law of Force and Acceleration

The force acting on a body is proportional to its mass times acceleration.

## Newton's Law of Action/Reaction

For every action there is an equal and opposite reaction force.

## Displacement

Distance and direction of an object's change in position from the starting point.

## Friction

A force that opposes motion between two surfaces that are in contact.

## Free Fall

The motion of a falling object when the only force acting on it is gravity.

## Momentum

The quantity of motion of a moving body, measured as a product of its mass and velocity.

## Projectile

An object thrown into the air with great force.

## Period

A length or portion of time.

## Frequency

The amount of times something happens in a certain amount of time.

## Centripetal Force

A force that causes an object to move in a circle.

## Centripetal Acceleration

Acceleration toward the center of a curved or circular path.

## Newton

A unit of measure that equals the force required to accelerate 1 kilogram of mass at 1 meter per second.

## Inertia

Resistance of an object to a change in its motion.