Physics - Motion and Energy

Scalar

A quantity described by magnitude (size) only.

Vector

A quantity described by both magnitude (size) and direction.

Weight

The downward force exerted by gravity on an object, calculated as W = m imes g.

Distance

How far an object has moved, scalar quantity.

Displacement

The direction and distance from the starting point to the final position of an object, vector quantity.

Speed

How fast an object is moving, scalar quantity.

Velocity

The speed of an object in a given direction, vector quantity.

Acceleration

The change in velocity over time, a vector quantity.

Momentum

The product of an object's mass and its velocity, vector quantity. All moving objects have this property

Conservation of Momentum

The principle that the total momentum of a closed system before a collision is equal to the total momentum after the collision.

Newton's First Law

An object will remain at rest or in uniform motion unless acted upon by an unbalanced force. (Inertia)

Newton's Second Law

F = ma, where force is the product of mass and acceleration.

Newton's Third Law

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

Energy

The ability to do work, measured in Joules (J).

Work

The energy transferred when a force moves an object a certain distance in a particular direction.

Kinetic Energy

Energy of motion, depending on speed and mass.

Potential Energy

Stored energy due to position or shape.

Law of Conservation of Energy

Energy cannot be created or destroyed, only transformed from one form to another.

Efficiency

A measure of how well a device converts input energy into useful output energy.

Sankey Diagram

A visual representation showing the input energy, useful output energy, and wasted energy.

Power

The rate at which energy is transferred, measured in Watts (W).

SUVAT

S - displacement (m)

U - initial velocity (ms^-1)

V - final velocity (ms^-1)

A - acceleration (ms^-2)

T - time (s)