Dynamics

Define net/resultant force

Overall force acting on an object

What do forces do, its equation and its standard and SI base unit

A force changes an objects speed, direction or shape

F = ma

F = resultant force, Newtons, N, kgms^-2

m = mass, kg

a = acceleration, ms^-2

Define 1 newton

The force that gives a 1kg object an acceleration of 1ms^-2

What is a fluid?

A liquid or gas

What happens when a resultant force acts on an object?

When a resultant force acts on an object with mass, it will accelerate.

What direction does acceleration act?

The same direction as the resultant force

What do unbalanced forces cause?

The resultant force to be >0

What are all the commonly occurring forces?

Weight

Friction

Drag/Air resistance

Upthrust/Buoyancy

Normal contact force

Define weight and its equation

Gravitational force acting on object through its centre of gravity

W = mg

W = weight, N, kgms^-2

m = mass, kg

g = acceleration of free fall, 9.81ms*-2

Define friction

The force when two objects rub against eachother

Define drag/air resistance and what is it directly proportional to?

The resistive force on an object travelling through a fluid, it acts against the direction of motion

Drag ∝ Speed²

Define tension

The force within a stretched cable/rope

Define upthrust/buoyancy and its equation

The upward force acting on an object in a fluid

U = Vρg

U = upthrust, N, kgms^-2

V = volume, m³

ρ = density, kgm^-3

g = acceleration of freefall, 9.81ms^-2

Define normal contact force

The force when an object rests upon another object acting perpendicular to the plane of contact

What do free body diagrams look like?

Forces represented as vector arrows, scaled to magnitudes

What do objects on a slope look like?

Resolve vectors into 2 components parallel and perpendicular to the slope