AQA GCSE: Physics - Forces Triple NA

Vector

A quantity that has magnitude and direction

Newton's First Law of Motion

An object in motion will remain in motion unless acted upon by another force

Newton's Second Law of Motion

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

Newton's Third Law of Motion

For every action there is an equal and opposite reaction

Speed

The distance an object travels per unit of time

Velocity

The distance an object travels per unit of time in a given direction

Equilibrium

A state where all the forces acting on an object are in balance

Friction

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

Terminal Velocity

The velocity at which the forces of friction and weight are equal

Tension

The force in a stretched object

Weight

The force of gravity on an object

Displacement

The distance traveled in a given direction

Distance

The length of a path between two points

Scalar

A physical quantity that has magnitude only.

Magnitude

The size of a quantity

Scale Diagram

Driving Force

The force that makes an object move

Resultant Force

The overall effect of all the forces on an object.

Free-Body Force Diagram

A diagram showing all the forces acting on an object

Moment

The turning effect of a force

Effort

The force applied to the load

Force Multiplier

A lever where the load is bigger than the effort.

Pivot

The point of rotation

Moment Equation

= Force × Perpendicular Distance

=Fd

Gear

A rotating wheel with teeth that transfers motion and forces

Centre Of Mass

a point representing the mean position of the matter in a body or system.

Principle Of Moments

For an object that is not turning:

The sum of all clockwise moments = The sum of all anti-clockwise moments

Parallelogram of Forces (Triple Topic)

A geometrical method of finding the resultant force of two forces that are not parallel

Resolution of Forces (Triple Topic)

Splitting a resultant force into two forces that act perpendicular to each other

Gradient

The rate of inclination

Acceleration

The rate at which velocity changes

Distance-Time Graph

Deceleration

The rate at which an object slows down

Velocity-Time Graph

Distance Traveled (Triple Topic)

The area beneath the line on a Velocity-Time graph

Tangent (Triple Topic)

A straight line that touches a curve at one point.

Inertia (Triple Topic)

The tendency of an object to resist a change in motion

Gravitational Field Strength

The force on a 1 kg object due to gravity

Stopping Distance

The shortest distance a car can safely stop in

= Thinking Distance + Braking Distance

Thinking Distance

The distance travelled by the vehicle in the time it takes the driver to react

Braking Distance

The distance travelled by a vehicle during the time that its brakes act.

Acceleration Equation (Triple Topic)

v²=u²+2as

Final Speed² = Initial Speed² + 2×acceleration×distance

Momentum (Triple Topic)

The product of an object's mass and velocity

Momentum Equation (Triple Topic)

=mass×velocity

=mv

Conservation of Momentum (Triple Topic)

In a closed system, the total momentum before an event is equal to the total momentum after the event

Closed System

A system in which no matter is allowed to enter or leave

Impact Force (Triple Topic)

The force that occurs between two objects colliding with each other

Crumple Zones (Triple Topic)

Areas at the front and back of car which crumple upon impact increasing impact time

Safety Helmets (Triple Topic)

A Helmet designed to increase the impact time of a collision

Elastic

An object that returns to its original shape after being deformed

Directly Proportional

When a graph of two variables is a straight line passing through the origin

Limit of Propertionality

The smallest force stretches a spring more than predicted by Hooke's Law

Hooke's Law

The law stating that the stress of a solid is directly proportional to the strain applied to it.

Hooke's Law Equation

Force = Spring Constant×Extension

F=ke

Pressure

Force per unit area.

Fluid Pressure Equation (Triple Topic)

=Height × Density × Gravitational Field Strength

=hρg

Atmospheric Pressure

The pressure caused by the weight of the atmosphere

Upthrust (Triple Topic)

The upward force water exerts on an object