WEIGHT

We know that the earth attracts every object
with a certain force and this force depends
on the mass (m) of the object and the
acceleration due to the gravity (g). The weight
of an object is the force with which it is
attracted towards the earth.
We know that
F = m × a, (10.13)
that is,
F = m × g. (10.14)
The force of attraction of the earth on an
object is known as the weight of the object. It
is denoted by W. Substituting the same in
Eq. (10.14), we have
W = m × g (10.15)
As the weight of an object is the force with
which it is attracted towards the earth, the
SI unit of weight is the same as that of force,
that is, newton (N). The weight is a force acting
vertically downwards; it has both magnitude
and direction.
We have learnt that the value of g is
constant at a given place. Therefore at a given
place, the weight of an object is directly
proportional to the mass, say m, of the object,
that is, W m. It is due to this reason that
at a given place, we can use the weight of an
object as a measure of its mass. The mass of
an object remains the same everywhere, that
is, on the earth and on any planet whereas
its weight depends on its location.