question_answer

A uniform rod of length \[L\] and mass 18 kg is made to rest on two measuring scale at its two ends. A uniform block of mass 2.7 kg is placed on the rod at a distance \[L/4\] from the left end. The force experienced by the measuring scale  on the right end is

A)  18 N            

B)  96 N

C)  29 N            

D)  45 N

Correct Answer: B

Solution :

 Taking moment about O, we get \[2.7\,g\times \frac{L}{4}+18g\times \frac{L}{2}=xg\times L\] \[\Rightarrow \] \[\frac{38.7g}{4}=xg\] or \[xg=96\,N\]