Forces

Scalar

quantity that has a magnitude but no direction

Vector

quantity that has a magnitude and a direction

What are examples of scalar?

speed, mass, time

What are examples of vector?

velocity, weight, forces

Define force

a push or pull that acts on an object

Examples of contact forces

friction, air resistance, reaction force

Examples of non-contact forces

weight, electrostatic, magnetic

Define contact forces

forces that require objects to be physically touching

Define non-contact forces

forces that allow objects to be physically separated

field

an area around one object where another would feel a force

gravity

Force of attraction between any objects that have mass

mass

number of particles in an object

weight

force on an object caused by gravity

What is an equation that links weight, mass and gravitational field strength?

W = m x g

Define centre of mass

the point at which mass can be thought of as concentrated or where the lines of symmetry cross

resultant force

single force that has the same effect as all of the original forces acting together

What does Hooke’s Law declare?

Force is proportional to the extension up to a limit of proportionality

What is Hooke’s Law?

F = k x e

What is meant by the limit of proportionality of a spring?

The maximum amount a spring can stretch until it can no longer revert to its original shape once the force has been removed.

thinking distance

the distance the car travels in the split second between a hazard appearing and the driver applying the brakes

braking distance

the distance the car travels during its acceleration, whilst the brakes are being applied

How do you find the total stopping distance?

thinking distance + braking distance

What are some factors that could affect thinking distance?

phone/ distractions, drugs, alcohol, age, tiredness, caffeine

What are some factors that could affect braking distance?

brakes, speed, weather, road surface, tyres, mass of car

work

amount of energy transferred when a force moves an object

What equation links work done, force and distance?

W = F x d