a mass m slides under the action of gravity inside a frictionless tube which is bent in the shape of a helix of radius a and pitch angle α. 34 kinematics: the description of motion the geometric axis of the helix is vertical. if the mass starts from rest at t = 0 from the point z-0 and φ = 0, find the er, e and ez components of the force exerted by the particle on the helix as a function of time