Given,
Length of each side of the cube, l=10 cm=0.1 m
Density of water, ρ=1000 kg m−3
Acceleration due to gravity, g=10 m s−2
Volume of the cube, V=l3=(0.1)3=0.001 m3
Archimedes' principle states that the buoyant force acting on an object is equal to the weight of the fluid displaced by it.
In the given case, volume of cube is equal to the volume of water displaced.
Mass of water displaced (m) = Density of water × Volume of water displaced
⇒m=1000 kg m−3×0.001 m3
=1 kg
Weight of water displaced, W = mg
⇒W=1×10 =10 N
Hence, the buoyant force is 10 N.