Question

If at any time the displacement of a simple pendulum be 0.02 m, then its acceleration is 2 m/s². What is the angular speed of the pendulum at that instant?

• A. 100 rad/s
• B. 10 rad/s
• C. 1 rad/s
• D. 0.1 rad/s

Answer 1

Answer: (B)

10 rad/s

Answer 2

y = A sin (ωt + φ)

$\frac{dy}{dt} = A\omega\cos(\omega t + \varphi)$

$\frac{d^{2}y}{dt^{2}} = - A\omega^{2}\sin(\omega t + \varphi)$

= - ω² y

2 = ω² × 0.02

ω² =100 or ω = 10 rad/s