Answer: 400 N.
- A 400 N
- B 500 N
- C 300 N
- D 600 N
Correct answer: A. 400 N
Explanation: Decelerating while moving up means acceleration is downward, so N = m(g - a) = 50(10 - 2) = 400 N.
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.