Weight of a body is less in the mines. Why?
The weight of a body is less in the mines because when we move deeper the earth gravity decreases but our mass is always constant.
Why is it difficult to lift a big stone than a smaller one on the surface of the earth?
We all know that,
W = mg
W ∝ m since g is constant on the same surface.
So, if the mass is more, more force should be applied to overcome its weight.
Therefore, it is difficult to lift a big stone than a smaller one on the earth's surface.