Question

The period of a certain pendulum is 2.0 seconds and the mass of the pendulum Bob is 50g. The Bob is pulled aside through a horizontal distance of 8cm and then released. Find the displacement and kinetic energy of the Bob 0.7seconds after release

Answer 1

Answer

Angular frequency

$w=\frac{2\pi }{T}=3.14$ rad/sec

t=0.7sec

x₀=0.08m

Amplitude is given

$X=x_0sin wt$

$X=0.08\times sin(3.14\times0.7)$

X=0.064m

Now velocity

$V=X\times w=0.2$ m/s

So kinetic energy

$K=\frac{mV^2}{2}=4\times10^{-5}$ J