Answer:
1) T sin θ = m v^2 / R tension in string directed towards center
2) T cos θ = m g tension in string in vertical direction
sin θ / cos θ = tan θ = v^2 / (R g) dividing equations
3) θ = tan^-1 (v^2 / (R g))
From 2) T = m * g / cos θ where θ is given by 3)
(T depends on m)
v^2 / R = T sin θ / m centripetal acceleration using 1)
θ is given by 3)