Question

what is weight?mention its uses​

Answer 1

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Weight is defined as the force acting on an object under the influence of gravitational field. So it tells us the amount of gravitational acting on the object. Weight of an object is not a constant and depedns upon the strength of the force and where its kept.

It SI units are Newtons (N)

Sometimes it may happen that various items in a series may not be equal in terms of relative importance. In such cases weighted arithetic mean proves useful. Herein, weights are attached to different items as per their relative importance. 

Hope it helps !