Answer: mv2/L - mg.
- A mv2/L + mg
- B mv2/L - mg
- C mg - mv2/L
- D mv2/L
Correct answer: B. mv2/L - mg
Explanation: At top: T + mg = mv2/L (both toward center). So T = mv2/L - mg.
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.