Question

A solid block is attached to a spring scale. The reading on the scale when the block is completely immersed in water is 25.1 N , and the reading when it is completely immersed in alcohol of density 806 kg/m3 is 25.7 N .

What is the block's volume?

What is the block's density?

Answer 1

density of air da = 1.225 kg/m^3

density of water dw =1000kg/m^3

denisty of alcohol dl = 806 kg/m^3

weight=mg

mass =denisty /volume

Weight of block in water is Fnet = 25.1 N

Fnet = weight of block in air - weight of displaced water

Fnet = dbVg - dwVg

25.1 = dbV*9.8 - 1000V*9.8 ... (1)

Weight of block in alchohol is Fnet = 25.7 N

Fnet = weight of block in air - weight of displaced alchohol

Fnet = dbVg - dlVg

25.7 = dbV*9.8 - 806V*9.8 ... (2)

By sloving (1) and (2) we get

volume of block V = 0.000315 m^3

density of block db= 9115.66 kg/m^3