# Numerical - Bulk modulus, given volume, compressive force

Q.  What is the bulk modulus of a material, if a cube of 100 mm changes its volume to 4000 mm3 when subjected to compressive force of 2.5 x 106 N?
- Published on 21 Sep 15

a. 62.5 Gpa
b. 65 Gpa
c. 67.5 Gpa
d. 70 Gpa

#### Discussion

• Vishal raghuwanshi   -Posted on 06 Oct 18

K=[250/{4000/(100)^3}] is right here not cube of 4000 value
• Sravanthi   -Posted on 24 Nov 15
Given: Compressive force = 2.5 x 106 N, change in volume = 4000 mm3, Side of cube = 100 mm

Formula: 1) σ = P/A

Stress is defined as the force per unit area.

2) K = δp / ( δV/V)

here, K is bulk modulus , δV/V is the change in volume

Solution:

1) σ = P/A

Area of cube = (100)2 and Compressive force = 2.5 x 106 N

σ = 2.5 x 106 / (100)2 = 250 N/mm2

2) Bulk modulus K = δp / ( δV/V)

K = 250 / (4000 /100)3

K = 62500 Mpa = 62.5 GPa

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