Which of the following statement (s) is (are) correct ?

Options

A. If there is no friction work needs to be done to move a body up an inclined plane
B. If there were no friction moving vehicles could not be stoped even by locking the brakes
C. As the angle of inclination is increased the normal reaction on the body placed on it increases
D. A duster weighing `0.5kg` is pressed against a verticalboard with a force of `11N` if the coefficient of friction is `0.5` the work done in rubbing it upward through a distance of `10cm` is `0.55 j`

Answer

a,b

Explanation

If there is no friction the work need to be done to move a body up a rough inclined plane but work has to be done against gravity Therefore this is correct
(b) If there is no friction moving vehicles could not be stopped because vehicles are stopped by friction Therefore this is correct
(c) As `R = mg cos alpha`
:. R decreases as alpha increases
Here `F = 0.5kg f + mu R`
`F = (0.5 xx 10 + 0.5 xx 11) N = 10.5 N`
Work done `W = F xx s = 10.5 xx 0.1 = 1.05 j`.