Forces:
Free fall
An object in free fall is falling solely under the
influence of gravity
On Earth, all free-falling objects accelerate towards
Earth at a rate of 9.81 m s−2
In the absence of air resistance, all bodies near the
Earth fall with the same acceleration regardless of
their mass
Mass v Weight
An object’s mass always remains the same,
however, its weight will differ depending on the
strength of the gravitational field on different planets
For example, the gravitational field strength on the
Moon is 1.63 N kg-1, meaning an object’s weight will
be about 6 times less than on Earth
, On the moon, your mass will stay the same but
your weight will be much lower
Although you only need to memorise g on Earth, its
value on other planets in our solar system is given in
the diagram below. Notice how much this varies
according to the size of the planet
Free fall
An object in free fall is falling solely under the
influence of gravity
On Earth, all free-falling objects accelerate towards
Earth at a rate of 9.81 m s−2
In the absence of air resistance, all bodies near the
Earth fall with the same acceleration regardless of
their mass
Mass v Weight
An object’s mass always remains the same,
however, its weight will differ depending on the
strength of the gravitational field on different planets
For example, the gravitational field strength on the
Moon is 1.63 N kg-1, meaning an object’s weight will
be about 6 times less than on Earth
, On the moon, your mass will stay the same but
your weight will be much lower
Although you only need to memorise g on Earth, its
value on other planets in our solar system is given in
the diagram below. Notice how much this varies
according to the size of the planet
