With what force is the spring stretched with which a bar of brass with a volume of 40 cm3 is suspended

With what force is the spring stretched with which a bar of brass with a volume of 40 cm3 is suspended to calculate the K of the spring if it is stretched by 4 cm

Data: V is the volume of the brass bar suspended from the spring (V = 40 cm3 = 4 * 10-5 m3); Δx – known tension (deformation) of the spring (Δx = 4 cm = 0.04 m).

Const: ρl – density of brass (ρl = 8500 … 8700 kg / m3, assumed ρl = 8600 kg / m3); g – acceleration due to gravity (g ≈ 10 m / s2).

1) The tensile force of the spring: Fcont = Ft = mb * g = ρl * V * g = 8600 * 4 * 10-5 * 10 = 3.44 N.

2) Spring rate: k = Fcont / Δx = 3.44 / 0.04 = 86 N / m.

Answer: The spring is stretched with a force of 3.44 N, its stiffness is 86 N / m.