- (B) Work done by gravity is negative because the gravitational force opposes the upward motion.
- (E) Work done by air resistance is always negative because it opposes motion.
- Other statements are incorrect because:
- (A) Work done by a man is positive as the applied force is in the direction of displacement.
- (C) Work done by friction is negative, not positive.
- (D) Work done is zero only if there is no displacement, not due to roughness.
A(g) $ \rightarrow $ B(g) + C(g) is a first order reaction.
The reaction was started with reactant A only. Which of the following expression is correct for rate constant k ?
$\mathrm{KMnO}_{4}$ acts as an oxidising agent in acidic medium. ' X ' is the difference between the oxidation states of Mn in reactant and product. ' Y ' is the number of ' d ' electrons present in the brown red precipitate formed at the end of the acetate ion test with neutral ferric chloride. The value of $\mathrm{X}+\mathrm{Y}$ is _______ .
Read More: Work and Energy