2004 · Q38
38. Weight of a body on the surface of the earth is W1. The weight of the same body is W2 at a height of 500 metres above the surface, and W3 at a depth of 500 metres below the surface of the earth. Which one of the following is the correct relation?
General SciencePhysics
- AW3 > W1 > W2
- BW1 > W2 ; W1 > W3
- CW1 < W2 < W3
- DW2 > W3 > W1
Explanation
Gravity weakens both above the earth's surface (falling with 1/r²) and below it (the enclosed mass shrinks with depth), so a body weighs less at 500 m above the surface (W2) and at 500 m below it (W3) than on the surface (W1). Both W2 and W3 are therefore less than W1, which is exactly what "W1 > W2 ; W1 > W3" states.