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Gravity
Relationship between mass and weight
Mass can be measured
with a
balance whereas weight can be measured with a dynamometer.
Several measures of masses and weights of different objects can be used
to compare them and establish an eventual relationship between them.
The
following table indicates in its columns the mass, the weight and the
ratio between these two quantities (W / m)
Object 
Object
1 
Object 2 
Object 3 
Object 4 
Mass m
(in kg) 
0,1 
0,2 
0,5 
1

Weight W
(In N) 
1 
2 
5 
10 
Ratio
( W : m ) 
10 
10 
10 
10 
The ratio W:m
remains constant ( its value is 10 ), such a
result shows that weight is proportional to mass: on Earth, the weight
of an object correspond to roughly ten times its mass.
The coefficient of
proportionality between weight and mass is
denoted by g and called
gravitational field strenght.
The
gravitational field strenght is expressed in newton per kilogram ( N/kg
) and its value on Earth is nearly 10 N/kg. More accurate measures would
have led to a result of 9,81 N/kg
The
proportionality between weight and mass lead to the following
relationship:
W = m x g
With:
W: Weight
(in newton)
m: mass (in
kilogram)
g:
gravitationnal field strenght (in newton per kilogram)
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