How do you find the position of a pendulum as a function of time?
Mass of bob: 2.0kg
String length (l): 3.0m
The pendulum is displaced as a distance of 0.35m from the equilibrium point and is then released. After 100 swings the maximum displacement of the pendulum has been reduced to 0.15m.
Period (T) of a pendulum: T = 2π√(l/g)
The Attempt at a Solution
The answer to the problem is f(t) = 0.35cos(1.81t) but I am not understanding how the 0.35 or the 1.81t is coming into play because I figured that if the angle is the point where the equilibrium point and the place where the pendulum is attached to a wall then the 0.35 would be opposite of this angle, not the adjacent of hypotenuse of the triangle created from the displacement of the pendulum. I also figured that the 0.35 was what the displacement was and I do not understand where the 1.81 came from at all.