Question

Two blocks are connected by a massless string through an ideal pulley as shown. A force of 22N is applied on block B when initially the blocks are at rest. Then speed of centre of mass of block A and block B, 2 sec, after the application of force is (masses of A and B are 4 kg and 6 kg respectively and surfaces are smooth) –

• A. 1.4 m/s²
• B. 1 m/s²
• C. 2 m/s²
• D. None of these

Answer 1

Answer: (A)

1.4 m/s²

Answer 2

F – 2T = 6a and T = 4 × 2a

\F – 16 a = 6a

Ž a = $\frac { F } { 22 }$ Ž a = 1m/s²

\ a_CM = $\frac { 6 \times 1 + 4 \times 2 } { 10 }$ = 1.4 m/s²