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 the weight of the body is more in Terai but less in mountains?
The value of acceleration due to gravity 'g' is inversely proportional to the square of the radius of any heavenly body.
Here, g ∝ 1/(R+h)2 where h is the height of surface from R.
So, if the height increases, the 'g' will decrease. There is more height in the mountain than that in Terai. So, 'g' is higher in Terai than in the mountaions.
From, W = mg
W ∝ g
So, W is higher in Terai than in the mountains.