Physics
posted by Allan .
A bead of mass m slides without friction on a vertical hoop of radius R . The bead moves under the combined action of gravity and a spring, with spring constant k , attached to the bottom of the hoop. Assume that the equilibrium (relaxed) length of the spring is R. The bead is released from rest at θ = 0 with a nonzero but negligible speed to the right.
What is the magnitude of the force the hoop exerts on the bead when θ = 90∘ ? Express your answer in terms of m, R, k, and g.

sqrt(( (2*sqrt(2)2)*k*R^2)/m+2*g*R)
(2*(sqrt(2)1)*k*R)+(2*m*g)((sqrt(2)1)*(k*R)*(1/sqrt(2)))