Equilibrium and Forces

Fact Sheet 1

Definition of Equilibrium 1 (being in equilibrium)

An object is in equilibrium if it is moving in a straight line at a constant speed. This includes an object remaining at rest.

Definition of Equilibrium 2 (balance)

Forces acting on an object in equilibrium are balanced.

Force 1 (what is force)

A force is a push or pull that acts on an object.

Force 2 (force measure)

Force is measured with a spring scale or platform scale.

Force 3 (force units)

The units of force are Newtons (N).

Mass and Weight 1 (what is mass)

Mass tells how much material is contained in an object.

Mass and Weight 2 (mass units)

The units of mass are kilograms.

Mass and Weight 3 (what is weight)

Weight is the force of a planet acting on an object.

Mass and Weight 4 (n/kg)

On earth's surface, the gravitational field is 10 Newtons per kilogram (N/kg). This means that on earth, 1 kg of mass weighs 10 N.

Normal force 1 (what is normal force)

A normal force is the force of a surface on an object in contact with that surface.

Normal force 2 (how does normal force act)

A normal force acts perpendicular to a surface.

Normal force 3 (how is normal force measured)

A platform scale reads the normal force.