Observations and Conclusions
From the experiment we find that the slope of the graph (weight in N against mass in kg) is a straight line going through the origin, so :
weight α mass
weight = constant x mass
The value which remains constant, in this experiment, is the pull of the Earth's gravity, and so:
weight = mass x gravity
W = m g
In this equation, weight is measured in N, mass in kg gravity in Nkg -1.
Weight is dependant on gravity and so by using the above equation you can convert a mass into a weight and vice versa. As a consequence, if the gravity is zero the weight is zero:
W = m x 0
So an object in space is weightless.
We also find that the weight of a 1 kg mass is 9.81 N.
We usually use 10N to make calculations easier : this means that 1N is the weight of an average sized apple!
Gravity and therefore weight, varies slightly depending on where you are on the Earth:
In Paris and London : g = 9.81 Nkg -1