Forces

Non-contact

acts at a distance without any contact between bodies due to the action of a field

Non-contact forces

• weight

• electrostatic

• magnetic

weight

force of gravity pulling on a mass

electrostatic

forces between charged objects

magnetic

forces between magnets

Contact

acts between objects that are physically touching

Contact forces

• upthrust

• friction

• drag

• normal reaction

• driving force

• tension

Upthrust

buoyant force from water (pushes up)

friction

opposing motion when two solids are in contact

Water resistance (drag)

opposing motion in water

Air resistance (drag)

opposing motion in air

normal reaction

push from surface

driving force

forward force from engines

tension

reaction force to an extension / compression of objects

mass

measure of how much matter an objects is made of

fixed property

weight

depends on mass & gravitational field strength

formula for weight

W=mg

What is Newton’s first law?

An object in the same state of motion will remain the same unless a resultant force acts upon it

What is Newton’s second law?

F=m x a → resultant force = mass (kg) x acceleration (m/s²)

What is Newton’s third law?

When two objects interact the forces they exert on each other are equal and opposite

equation for acceleration

a = (v - u) / t

Resultant forces

the sum of all forces represented as one force