Answer: Elevator moves up at constant speed.
- A Elevator moves up at constant speed
- B Elevator accelerates upward
- C Elevator accelerates downward
- D Elevator is in free fall
Correct answer: A. Elevator moves up at constant speed
Explanation: At constant speed (no acceleration), N = mg. The person feels their normal weight.
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.