question_answer

A sphere of mass m is held between two smooth inclined walls. For sin \[37{}^\circ =3/5,\] the normal reaction of the wall (2) is equal to :

A) mg

B) \[mg\sin {{74}^{o}}\]

C) \[mg\cos {{74}^{o}}\]

D) none of the above

Correct Answer: A

Solution :

[a] Using Lami's theorem \[\frac{mg}{\sin ({{180}^{\circ }}-{{37}^{\circ }})}=\frac{{{N}_{2}}}{\sin ({{180}^{\circ }}-{{37}^{\circ }})}\] \[\therefore \]      \[{{N}_{2}}=mg\]