Answer: tan(theta).
- A tan(theta)
- B sin(theta)
- C cos(theta)
- D sin(2*theta)
Correct answer: A. tan(theta)
Explanation: At limiting equilibrium: mg sin(theta) = mu mg cos(theta). So mu = tan(theta).
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.