NEET Physics: Work and Energy questions with solutions

Q1. Assertion A body is moved from \( x=2 \) to \( x=1 \) under a force \( \boldsymbol{F}=\mathbf{4} \boldsymbol{x} \), the work done by this force is negative. Reason Force and displacement are in opposite directions.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Answer: Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

The force is along the positive x-direction, while the body moves from x=2 to x=1, so the displacement is in the negative x-direction. Since force and displacement are opposite, their dot product is negative, making the work negative.