1. The problem statement, all variables and given/known data A mass,m, hangs from a string and swings with a frequency of 0.8 Hz with a maximum displacement of 0.1 rad. The equation of motion is given by x=Acos(ωt). A) What is the length of the string? B) What is the maximum displacement of the mass in meters? C) What is the velocity of the mass as a function of time? Leave the answer as a function of m,g,L, and θmax (Hint: Take the derivative of the equation of motion). D) What is the restoring force acting on the mass as a function of time? Leave the answer as a function of m,g,L, and θmax (Hint: Find the acceleration) 2. Relevant equations ω=sqrt(g/l) ω=2pif 3. The attempt at a solution for part a) ω = 2pif and ω = sqrt(g/l) (since this is a simple pendulum) so 2pif=sqrt(g/l) or l=g/(4pi^2f^2) = 9.8/(4pi^2(.8)^2) = .39m for part b i cant figure out how to get .1 rads into meters. this is my attempt so far (.1 rad) (cycle/2pi rad) (second/.8cycle) = .02 seconds for part c take the derivative dx/dt = d/dt(Acos(sqrt(g/l)t)) v = -Asin(sqrt(g/l)t)(sqrt(g/l) im guessing the theta max that the question wants v defined in terms of will be part of A part d a = dv/dt = d/dt(-Asin(sqrt(g/l)t)(sqrt(g/l)) = -Acos(sqrt(g/l)t)(g/l) then use F = ma = -kx m * -Acos(sqrt(g/l)t)(g/l) any feedback?