Answer: (W 1 + W 2 )/2.
- A W<sub>1</sub> + W<sub>2</sub>
- B (W<sub>1</sub> + W<sub>2</sub>)/2
- C W<sub>1</sub> - W<sub>2</sub>
- D (W<sub>1</sub> - W<sub>2</sub>)/2
Correct answer: B. (W<sub>1</sub> + W<sub>2</sub>)/2
Explanation: W<sub>1</sub> = m(g+a), W<sub>2</sub> = m(g-a). Adding: W<sub>1</sub>+W<sub>2</sub> = 2mg. True weight = mg = (W<sub>1</sub>+W<sub>2</sub>)/2.
Free-body diagram of a block on an incline: weight (mg) resolves into mg sinθ along the slope and mg cosθ into the slope, balanced by the normal force N and friction f.
Concept context
Newton's three laws, friction, circular motion, and free body diagrams.