1. The problem statement, all variables and given/known data A mass of 3.50 kg is suspended from a 1.59 m long string. It revolves in a horizontal circle as shown in the figure. The tangential speed of the mass is 2.99 m/s. Calculate the angle between the string and the vertical. 2. Relevant equations a_c = v^2/r F = m*a_c tanθ=sinθ/cosθ sin^2θ=1-cos^2θ 3. The attempt at a solution Vertical: T*cos(θ)-m*g=0 → T=(m*g)/cos(θ) Horizontal: T*sin(θ) = m*a_c Combined the two: ((m*g)/cos(θ))sin(θ)=m*a_c → m*g*tan(θ)=m*a_c → g*tan(θ)=a_c we know that a_c=v^2/r, plug that in to get g*tan(θ)=v^2/r r=L*sin(θ) → g*tan(θ)=v^2/(L*sin(θ)) I cannot get past this point and the notes on the problem say that a quadratic equation needs to be solved at some point.