Question

A man grows into a giant such that his linear dimensions increase by a factor of 9. Assuming that his density remains same, the stress in the leg will change by a factor of

(a) 9 (b) 1/9 (c) 81 (d) 1/81

Answer 1

Answer - (a)

Stress F/A = Mg/A
T₁/T₂ = M₁/M₂ = A*L₂ρ/A₄ρ = 9

Stress

The stress applied to a material is the force per unit area applied to the material. The maximum stress a material can stand before it breaks is called the breaking stress or ultimate tensile stress.

Tensile means the material is under tension. The forces acting on it are trying to stretch the material. Compression is when the forces acting on an object are trying to squash it.

The equation above is used to calculate the stress.

stress = stress measured in Nm^-2 or pascals (Pa)
F = force in newtons (N)
A = cross-sectional area in m²