A simple pendulum, 2.0 m in length, is released from rest when the support string is at an angle of 25 from the vertical. What is the speed of the suspended mass at the bottom of the swing?

2 answers

Let A be the pendulum angle, which vaires sinusoidally with time. R is the pendulam length

R sin A = X

Xm = 2.0 sin 25 = 0.845 m is the oscillation amplitude (measured horizontally)

X = Xm sin (w t)
is the equation of motion

w is the angular frequency
w = sqrt(g/R) = 2.21 rad/s

Vmax = w*Xm = 2.21 rad/s*0.845 m
= 1.87 m/s
What is the mathmatical formula