Question

Two blocks A and B of mass $m$ and $4m$ are connected with a rod PQ of length l and mass $6m$ through light strings. There is no friction anywhere. If the system is released from rest and the rod PQ slides on the incline, then for the position shown in the figure, the ratio of the speeds of the mass A to that of the mass B is:

• A. $\frac{\sin \alpha }{\sin \beta }$
• B. $\frac{\cos \alpha }{\cos \beta }$
• C. $\frac{cos(\alpha +\beta )}{cos(\alpha -\beta )}$
• D. $\frac{sin(\alpha +\beta }{sin(\alpha -\beta )}$

Answer 1

Answer: (B)

Constraint equation :
$V_A\cos \beta =V_B\cos \alpha$

$\frac{V_A}{V_B}=\frac{\cos \alpha }{\cos \beta }$