UNit 8 Vocabulary: Force and Motion (includes Newton's Laws)

Speed

Distance traveled in a certain amount of time

Speed formula: S=d/t

Units: meters per second (m/s), miles per hour (mph), kilometers per hour (km/h)

Velocity

Speed with direction

Units: meters per second (m/s), miles per hour (mph), kilometers per hour (km/h) + direction

Distance

Space between two points

Units: meters (m), miles (mi), kilometers (km)

Acceleration

Change in velocity over time. Can when object speeds up, slows down or changes direction

Positive acceleration: object speeds up

Negative acceleration: object slows down

Balanced Forces

DO NOT cause a change in motion because they are EQUAL in size and ARE opposite in direction and act on the SAME OBJECT.

Force

A push or a pull. Measured using the unit Newtons (N)

Friction

A force that opposes motion

Gravity

A force that pulls objects toward each other

Inertia

Resistance of an object to change its motion.

More mass = more inertia

Less mass = less inertia

Newton's Third Law of Motion

Law of Action-Reaction. For every action, there is equal and opposite reaction. These forces act on different objects.

Newton's First Law of Motion

Law of Inertia. An object at rest will stay at rest and an object in motion will stay in motion and in the same direction, unless acted upon by an external unbalanced force.

Mass

The amount of matter in an object

Newton's Second Law of Motion

The acceleration of an object depends on the mass of the object and the amount of force applied.

Force = mass X acceleration

Newtons (N)

Unit to measure Force

Unbalanced Forces

ALWAYS cause a change in motion. They are NOT equal in size, but ARE opposite in direction and act on the same object.

Weight

A measure of the gravitational force exerted on an object.

Motion

An object's change in position relative to a reference point.

Reference point

A place or object used for comparison to determine if an object is in motion