Answer:
Y = 78.13 x 10⁹ Pa = 78.13 GPa
Explanation:
First we will find the centripetal force acting on the wire as follows:
F = mv²/r
where,
F = Force = ?
m = mass of rock = 0.34 kg
v = speed = 19 m/s
r = length of wire
Therefore,
F = (0.34)(19)²/r
F = 122.74/r
now, we find cross-sectional area of wire:
A = πd²/4
where,
A = Area = ?
d = diameter of wire = 1 mm = 0.001 m
Therefore,
A = π(0.001)²/4
A = 7.85 x 10⁻⁷ m²
Now, we calculate the stress on wire:
Stress = F/A
Stress = (122.74/r)/(7.85 x 10⁻⁷)
Stress = 1.56 x 10⁸/r
Now, we calculate strain:
Strain = Δr/r
where,
Δr = stretch in length = 2 mm = 0.002 m
Therefore,
Strain = 0.002/r
now, for Young's modulus (Y):
Y = Stress/Strain
Y = (1.56 x 10⁸/r)/(0.002/r)
<u>Y = 78.13 x 10⁹ Pa = 78.13 GPa</u>
