Undamped Pendulum: Amplitude & Energy

[Electrifying]

An undamped pendulum of mass m = 10kg, and length L = 5m, is released at time t = 0 with an initial displacement θ(0) = 0.05 radians and an initial angular frequency ω(0) = 0.1 radians/s.

I need to calculate the amplitude of the oscillations in radians, and the total energy of the oscillations.

I have confused myself in my notes about where I need angular velocities, linear velocities and all sorts. I need to do this problem and another two related ones, hopefully if someone can show me the correct way to do this one I'll be able to do the other two myself.

Thanks in advance.

 

[jbsteele]

The amplitude of the oscillations in radians is given by the initial displacement, θ(0) = 0.05 radians.The total energy of the oscillations is given by the sum of the potential energy and kinetic energy of the pendulum:PE = mgL(1-cosθ)KE = ½mω2Etotal = mgL(1-cosθ) + ½mω2 = 10*5*(1-cos(0.05)) + ½*10*(0.1)2 = 25.0125 J