Question

In the given arrangement, strings and pulleys are light and all surface are frictionless. Assuming at t = 0, system is released from rest, find the speed of block A at t = 2 sec –

• A. 8 m/s
• B. 9 m/s
• C. 10 m/s
• D. None of these

Answer 1

Answer: (C)

10 m/s

Answer 2

The system can be redraw as

\ a = $\frac { 4 \mathrm { mg } } { 8 \mathrm {~m} }$ = $\frac { \mathrm { g } } { 2 }$ = 5 m/s²

\ v = u + at = 2 × 5 = 10 m/s