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Question:

A 0.1 kg mass is suspended from a wire of negligible mass. The length of the wire is 1 m and its cross-sectional area is 4.9 × 10⁻⁶ m². If the mass is pulled a little in the vertically downward direction and released, it performs simple harmonic motion of angular frequency 140 rad/s. If the Young's modulus of the material of the wire is n × 10⁹ Nm⁻², the value of n is?

8

4

2

1

Solution:

ω = √(YA/mL)
140 = √(n × 10⁹ × 4.9 × 10⁻⁶ / (0.1 × 1))
n = 4