Answer to Question #98334 in Mechanics | Relativity for ridwan

Question

A block of wood weighs 60g in air. A lead sinker weighs 70g in water. The sinker is attached to the wood and both together weighs 65g in water. Find the the relative density of the wood.

Answer 1

It is very likely that you have a mistake in the problem statement. The weight of two submerged bodies cannot be less than one submerged, including if a lead load is attached to a body whose density is less than the density of water (wood).

So, ideally, when rechecking data, it is necessary:

1) to take away the weight of the cargo in water from the weight of the wood with the load;

2) the strength of Archimedes will be numerically equal to the distribution of the mass of wood in air minus the mass of wood in water;

3) then, from the formula, find the volume of wood:

$$V = {F_A \over d_{water}g}$$

4) divide the mass of wood by the found volume (do not forget to translate the volume in cm³).