Question

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

• A. $2mg\cos \theta$
• B. $\frac{mg}{2}\cos \theta$
• C. $\frac{mg}{2}\sin 2\theta$
• D. $\frac{mg}{2}\sin \theta$

Answer 1

The correct option is A $2mg\cos \theta$

$T=N_{AB}sin\theta$

$T=mgcos\theta \ast sin\theta$

$=\frac{mgsin2\theta }{2}$