Question

1) 700 grams soil cube having an edge of length 10cm floats in water the volume of the cube outside the water is a) 700 centimetre cube b) 400 cm cube c) 300 cm cube d)100 centimetre cube 2) a cube of wood supporting 200 gram mass just floats in water when the mass is removed the cube rises by 2 cm the side of the cube isa) 4cm b) 9 CM c)10cm d)20cm​

Answer 1

Answer:

The weight of the cube is balanced by the buoyant force. The buoyant force is equla to the wieght of the water displaced. If a volume V of the cube is inside the water the weight of the displaced water =Vρg. Where rho is the density of water thus.

Vρg=(0.7kg)g

V=0.7kgρ=0.7kg1000kgm−3=7×10−4m^3=700cm^3

the total volume of the cube =(10cm)^3=1000cm^3

The volume outside the water is

1000cm^3−700cm^3=300cm^3