Question

In constructing a large mobile, an artist hangs an aluminum sphere of mass 6.0kg from a vertical steel wire 0.50m long and 2.5 × 10^-3 cm^2 in cross sectional area. On the bottom of the sphere he attendes a similar steel wire, from which he hang a brass cube of mass 10.0kg. for each wire, compute (a) the tensile strain and (b) the elongation?

Answer 1

Start here:
young's modulus = stress/strain= (F/Area)/(changeL/Loriginal)
So look up youngs modulus for steel.
Then you know Force (equal to the total weight below), you know area, and you know Length original of that wire. Calculate changeL That gives you b) on both wires.
for strain, strain= (F/Area)/youngs modulus