question_answer

On the horizontal surface of a truck, a block of mass \[1\,\,kg\] is placed \[(\mu =0.6)\] and truck is moving with acceleration \[5m/{{s}^{2}}\]. The frictional force acting on the block will be: \[(g=10\,\,m/{{s}^{2}})\]

A) \[6\,\,N\]                                           

B) \[5.88\,\,N\]

C)  \[7\,\,N\]                                          

D)  \[9\,\,N\]

Correct Answer: A

Solution :

The frictional force acting on the block but from figure,\[R=mg\] \[\therefore \]  \[f=\mu \,\,m\,\,g\] Here,\[\mu =0.6,\,\,m=1\,\,kg,\,\,g=10\,\,m/{{s}^{2}}\] \[\therefore \]  \[f=0.6\times 1\times 10=6\,\,N\] Note: Due to acceleration of truck, the block experiences a forward force                 \[F=ma=1\times 5=5N\] Since,\[f>F\] so block is not displaced from its previous position.