Question

A man weighing 800 N is hanging from a 2 mm diameter titanium wire with a cross-section of 3 x 10^-6 m^2. Will the wire break?

Answer 1

Answer:

Since stress is greater than ultimate strength, the wire will break.

Step-by-step explanation:

The titanium wire is experimenting an axial load. Ultimate strength equals $2.20\times 10^{8}\,Pa$. The wire shall break if and only if stress is at least equal to ultimate strength. The equation for axial stress ($\sigma$), measured in pascals, in the wire with circular cross-section is:

$\sigma = \frac{4\cdot F}{\pi\cdot D^{2}}$ (1)

Where:

$F$ - Axial force, measured in newtons.

$D$ - Cross-section diameter, measured in meters.

Please notice that axial force is the weight of the man hanging from wire.

If we know that $F = 800\,N$ and $D = 0.002\,m$, then the axial stress experimented by the titanium wire is:

$\sigma = \frac{4\cdot (800\,N)}{\pi\cdot (0.002\,m)^{2}}$

$\sigma \approx 2.546\times 10^{8}\,Pa$

Since stress is greater than ultimate strength, the wire will break.