A force is any push or pull on an
The units for force are Newtons (N) they are
equal to a kg m/s2.
F = ma
Weight is equal to mass times acceleration of
Fg = mg
Mass is measured in kg and does not change as
height changes. Weight does get less as you
move away from the center of Earth.
• Newton’s 3 laws
– 1st : Law of Inertia An object at rest
will stay at rest, an object in motion will
stay in motion, unless acted upon by an
– 2nd : F = ma An object will accelerate
in the presence of an unbalanced force.
The larger the mass the smaller the
– 3rd : For every action there is an equal
and opposite reaction.