question_answer

A block is resting on a piston which is moving vertically with SHM of period 1 s. At what amplitude of motion will the block and piston separate?

A)  0.2 m    

B)  0.25 m

C)  0.3 m                                   

D)  0.35 m

Correct Answer: B

Solution :

                 When maximum force just exceeds the weight of the body, then weight kept on the system will separate from the piston \[\therefore \]  \[mg=m{{\omega }^{2}}y\] \[\Rightarrow \]               \[y=\frac{g}{{{\omega }^{2}}}\] Given \[g=9.8\,\,m{{s}^{-2}},\,\omega =2\pi \] \[\therefore \]  \[y=\frac{9.8}{(2\pi )}=0.25\,m\]