Block B has mass m and is released from rest when it is on top of wedge A, which has a mass 3 m. Determine the tension in cord CD needed to hold the wedge from moving while B is sliding down A. Neglect friction :

2 mg cos θ mg/2 cos θ mg/2 sin 2θ mg sin 2θ

mg/2 sin 2θ

\(T = N \sin {\theta} \text{ and} N = mg \cos {\theta}\) \(T = mg \cos {\theta} \sin {\theta}\) \(T = \frac{mg}{2} \sin {2\theta}\)