question_answer

A block A of mass 7 kg is placed on a frictionless table. A thread tied to it passes over a frictionless pulley and carries a body B of mass kg at the other end. The acceleration of the system is: (given\[g=10\text{ }m{{s}^{-2}}\])

A)  \[100\,m{{s}^{-2}}\]                      

B)  \[3\,m{{s}^{-2}}\]          

C)         \[10\,m{{s}^{-2}}\]       

D)         \[30\,\,m{{s}^{-2}}\]

E)  zero

Correct Answer: D

Solution :

Net acceleration                                              \[a=\frac{{{M}_{2}}}{{{M}_{1}}+{{M}_{2}}}g\] \[=\frac{3}{7+3}\times 10=3\,m{{s}^{-2}}\]