I am trying to derive an expression for the Tension T in the massless bar in the given photo. Where there is a cart that is moving only in the x-direction and the bar is rotating around a point pivoted at the cart with angle theta. The expression that I have is deduced from: ∑ F (towards center) = Centripetal Acceleration Which gives: T - mg*cos(θ) = m * (θ (dot))2 *L Is this true? or I should add another force term that comes from the cart acceleration it self: M*x(double dot) * sin(θ)? Thanks!