Question

A solid weighs 6N in air and 5.2N when fully immersed in water. Calculate the density of the solid.

Answer 1

the weight of the object in air = 6N.
mg = 6
m = 0.6 kg

in water, the weight is 5.2 N, so the buoyant force shoud be 6 - 5.2 = 0.8N.
so as you know that upthrust = density * volume * acc. due to gravity
0.8 = 1000*vol.*10
vol.=0.00008 cubic metres.
density = mass/vol=0.6/0.00008=7500 kg/ cu. m