A block `m` is kept stationary on the surface of an accelerating cage as shown in figure. At the given instant, study the following statetments regarding the block.

i. Normal reaction performs positive work on the block.
ii. Frictional work done on the block is negative.
iii. No net work is done by normal reaction and friction on the block.
Now mark the correct answer.

Options

A. (a) Only statement (i) is correct.
B. (b) Only statement (ii) is correct.
C. (c) Only statement (iii) is correct.
D. (d) All the statements are correct.

Answer

A

Explanation

`ma` is pseudo-force.
We find that `mg sin theta` is equal to `ma cos theta`. So block remains stationary w.r.t. cage and there is no need of friction.
Statement (i) is correct because agnel between N and displacement is positive. Friction force acting on the block is zero, hence no work will be done by friction, so Statement (ii) is incorrect.