question_answer

A block of mass 5 kg is (i) pushed in case [A] and (ii) pulled in case , by a force F = 20 N, making an angle of \[30{}^\text{o}\] with the horizontal, as shown in the figures. The coefficient of friction between the block and floor is \[\mu =0.2.\]The difference between the accelerations of the block, in case [B] and case [A] will be : \[(g=10m{{s}^{-2}})\] [JEE Main 12-4-2019 Afternoon]

A) \[0m{{s}^{-2}}\]                 

B) \[0.8\,m{{s}^{-2}}\]

C) \[0.4\,m{{s}^{-2}}\]

D)   \[3.2\,m{{s}^{-2}}\]

Correct Answer: B

Solution :

\[{{N}_{1}}=60\]                              \[{{N}_{2}}=40\] \[{{a}_{1}}=\frac{10\sqrt{3}-0.2\times 60}{5}\]    \[{{a}_{2}}=\frac{10\sqrt{3}-0.2\times 40}{5}\] \[{{a}_{1}}-{{a}_{2}}=0.8\]