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Work, Energy And Power

Question
CBSEENPH11026368

A light string passes over a frictionless pulley. To one of its ends a mass of 8 kg is attached. To its other end two masses of 7 kg each are attached. The acceleration of the system will be

  

  • 10.2 g

  • 5.10 g

  • 20.36 g

  • 0.27 g

Solution

D.

0.27 g

free body diagram,

     

For body A, having mass m1 forces are given by

          m1a = T1 - m1 g                   ....(i)

For body B

            m2a = m2 g + T2 - T1            .....(ii)

For body C

            m3 a = m3g - T2                  ......(iii)

On solving Eqs. (i), (ii) and (iii), we get

            a = m2 + m3 - m1 gm1 + m2 + m3

 As      m1 = 8 kg, m2 = m3 = 7 kg

           a = 7 + 7  - 8 g22

            a = 622g

             a = 0.27 g