question_answer

A triangular block of mass M with angles \[30{}^\circ ,\]\[60{}^\circ \]and \[90{}^\circ \] rest with its \[30{}^\circ -90{}^\circ \] side on a horizontal table. A cubical block of mass m rests on \[60{}^\circ -30{}^\circ \]side. The acceleration which M must have relative to the table to keep m stationary relative to the triangular block is (assuming frictionless contact)

A) \[g\]                  

B)        \[g/\sqrt{2}\]

C) \[g/\sqrt{3}\]

D)        \[g/\sqrt{5}\]

Correct Answer: C

Solution :

[c] Use result, \[a=\text{gtan}\,\theta ,\]\[a=g\tan 30{}^\circ =g/\sqrt{3}\]