Question

All pulley shown in figure are light and there is no friction between pulley and string. Acceleration of pulley 'P' in figure is given by –

• A. g upward
• B. g downward
• C. zero
• D. None of these

Answer 1

Answer: (D)

None of these

Answer 2

Let acceleration of block A and B be a₁ and a₂ respectively and a_p be acceleration of pulley P.

\ Let tension in string be T

\ According to principle of virtual work

3T. a_p = T. a₁ + 8T a₂

\ a_p = $\frac { 9 \mathrm {~g} } { 3 } = 3 \mathrm {~g}$ (upwards)