question_answer

A block is kept on a frictionless inclined surface with angle of inclination a. The incline is given an acceleration a to keep the block stationary. Then, a is equal to                    [AIEEE 2005]

A) \[g/tan\alpha \]

B) \[g\text{ }\cos ec\alpha \]

C) \[g\]

D) \[g\text{ }tan\alpha \]

Correct Answer: D

Solution :

[d] If there is not a direct force on a body except contact force, then we must assume a pseudo force on the body in a direction opposite to the actual force and after that we conclude all the forces acting on the body.

In the frame of wedge, the force diagram of block is shown in figure. From free body diagram of wedge,

For block to remain stationary,

(along incline)