Given a cube of density 8900kg/m3 and length side 10cm

A- What do you mean by the "nature" of a cube?

B- Density x Volume
C- Relative to what?
D- If they are trying to teach you the relationship between mass and weight, they should teach you the correct value of g. On earth, it is 9.81 m/s^2 , not 10. It varies with location, planet and altitude.
Anyway, multiply mass (kg) by the N/kg number.

Nature often means solid,

liquid or gas. Typical solids have high densities and this figure would make it a solid. It is the same density as copper.

Relative density is relative to water, unless the material is otherwise specified.
As no temperature is given then use 1000 kg m^-3 for water, so the relative density is 8.9 (no units).

10 cm long,10 cm wide,and 10 cm high

A- To determine the nature of the cube, we need to compare its density with the density of a known substance. Density is defined as mass per unit volume.

B- To find the mass of the cube, we can use the formula:
mass = density * volume

Given:
Density = 8900 kg/m3
Length of the side = 10 cm = 0.1 m (since 1 cm = 0.01 m)

The volume of a cube = (side)3 = (0.1 m)3 = 0.001 m3

Therefore, the mass of the cube = 8900 kg/m3 * 0.001 m3 = 8.9 kg

C- To find the relative density of the cube, we need to compare it with the density of a reference substance. Relative density is a dimensionless quantity and is calculated by dividing the density of the given substance by the density of the reference substance.

Relative Density = (Density of the given substance) / (Density of the reference substance)

Since a reference substance is not provided, let's assume the reference substance as water, which has a density of 1000 kg/m3.

Relative Density = 8900 kg/m3 / 1000 kg/m3 = 8.9

Therefore, the relative density of the given cube is 8.9.

D- To find the weight of the cube, we can use the formula:
weight = mass * gravitational acceleration

Given:
Mass = 8.9 kg
Gravitational acceleration = 10 N/kg (as mentioned)

Weight = 8.9 kg * 10 N/kg = 89 N

Therefore, the weight of the cube is 89 N.