1. The problem statement, all variables and given/known data Calculate the torque, t about origin that must be applied to a particle for it to maintain a constant speed v along a cardiod. 2. Relevant equations t = r x f a = (r_dot dot - r*Θ_dot ^2) r_hat + (r*Θ_dot dot + 2 r_dot * theta_dot) theta_hat 3. The attempt at a solution Constant speed means that the derivative of the speed wrt time = 0 = magnitude of the acceleration. But then if the mag of the accleration is zero then everything turns to zero because it is all related. So I'm guess there is something else which constant speed implies and I am wrong. What is it?