Question

A cube of a material with a density of 4230 kg/m^3 has a volume of 0.00100 m^3 and a weight of 41.5 N. When the cube is placed in water with a density of 1000. kg/m^3, what buoyant force acts on the material?

Answer 1

The buoyant force is 9.8 N.

Step-by-step explanation:

The buoyant force acting on the material is called upthrust, and can be determined as;

Upthrust = density of liquid x volume of object x gravitational force

So,

density =
`(mass)/(volume)`

⇒ mass = density x volume

= 4230 x 0.001

= 4.23

mass of the material = 4.23 kg

But,

weight = mass x gravitational force

weight = 41.5 N, and mass = 4.23 kg, then;

41.5 = 4.23 x g

g =
`(41.5)/(4.23)`

= 9.811

g = 9.8 m/
`s^(2)`

Upthrust = 1000 x 0.001 x 9.81

= 9.81 N

The buoyant force is 9.8 N.