Question

Find velocity of ring B ($V_B$) at an instant as shown. The string is taut and inextensible:

• A. $\frac{1}{2}m/s$
• B. $\frac{\sqrt{3}}{4}m/s$
• C. $\frac{1}{4}m/s$
• D. 1 m/s

Answer 1

The correct option is D

1 m/s

As ring goes up the string between it and pulley will slack and as the block goes right it will stretch the string.

But the string is inelastic and has to be taut

So the velocity slacking the string and velocity stretching it should be equal

$V_{B}cos60$ = $V_{A}cos60$

$v_B$ = $1m/s$