Answer: (W1 + W2)/2.
- A W1 + W2
- B (W1 + W2)/2
- C W1 - W2
- D (W1 - W2)/2
Correct answer: B. (W1 + W2)/2
Explanation: W1 = m(g+a), W2 = m(g-a). Adding: W1+W2 = 2mg. True weight = mg = (W1+W2)/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.