Forces

Vector quantities: have a direction and a magnitude (magnutude means size), they are also called physical quantities:

• force, velocity, displacement, acceleration, momentum.

Scalar Quantities: only have a magnitude, no direction:

• speed, distance, mass, temperature, time.

Contact forces: (two objects have to be touching)

• Friction, air resistance, tension in ropes, normal contact force.

Non-contact forces:

• magnetic force, gravitational force, electrostatic force.

The forces of two objects interacting which are equal but are in opposite directions are called an interaction pair.

E.g: The earth and the sun are an interaction pair as they are attracted…