# Define weight. State its SI and CGS units.

60 views
in Physics
closed

Define weight. State its SI and CGS units.

+1 vote
by (44.3k points)
selected

The weight of a body is defined as the force with which the earth attracts it. Its SI unit is the newton and CGS unit is the dyne.

[Note : In the usual notation, the magnitude of the weight of a body on the earth s surface is W = $\frac{GmM}{R^2}$ = $m\frac{GM}{R^2}$ = mg.

Thus, W ∝ g. Hence, weight varies just like the acceleration due to gravity. It is maximum at the poles and minimum at the equator. It decreases with altitude (ft) and depth (d) below the earth’s surface. It becomes zero at the earth’s centre. At a height above the earth’s surface, W = $\frac{GmM}{(R+h)^2}$ at a depth d below the earth’s surface, W = $\frac{GmM(R-d)}{R^2}$. Weight has magnitude and direction (towards the earth’s centre). It is a vector quantity.]