Q. a body weighs 50 n in air and when immersed in water it weighs only 40 n. find its relative density.

The relative density is the ratio of a substance being measured with its reference which is usually water.

In hydrostatic weighing where force is involved, the formula to use is: 

RD= Density in air/ Density in air - Density in water 

Therefore = 50/50-40 = 50/10 = 5

RD= 5N

Iread this book last year so take this with a grain of salt.gene jumps from the tree to compete with finny due to the fact that gene is always trying to do better than finny. he is put under the grasp of peer pressure due to finny almost forcing him to do this. ever since he first jumped finny kept pressuring him to jump since he thought gene enjoyed jumping.rather than uses this answer you should probably just reread chapters 3-4