MOTION AND FORCES EDEXCEL

what is a vector quantity?

a quantity with magnitude and a direction.

what is speed?

distance travelled per unit time

is speed a scalar or a vector quantity?

scalar

what is velocity?

speed in given direction

what does area under velocity time graph show?

distance

what is weight?

the pull of gravitational force on an object

what is friction?

force that opposes motion

state hooke’s law

extension is directly proportional to the force applied until the limit of proportionality is reached

state the principle of moments

clockwise moment is equal to anticlockwise moment in a closed system

what is centre of mass?

the point at which the weight of the object acts.

state Newton's first law

An object at rest remains at rest, and an object in motion remains in motion at constant speed and in a straight line unless acted on by an unbalanced force.

state Newton's second law

Force (F) = mass (m) x acceleration (a)

state newton’s third law

Every action has an equal and opposite reaction.

The lower the centre of mass of an object

the greater the stability.

The greater the base area of an object

the greater the stability.

what is air resistance?

it is a frictional force that opposes motion in air. It slows down anything travelling through the air and may also cause the object to heat up.

what is acceleration?

Acceleration is the rate of increase in velocity with time.

what is stopping distance?

Stopping distance is the total distance covered by a vehicle from the moment the driver perceives a hazard until the vehicle comes to a complete stop.

what is momentum?

Momentum is a measure of how difficult it is to stop something that is moving.

what is momentum?