Answer: 15 N.
- A 3 N
- B 5 N
- C 15 N
- D 25 N
Correct answer: C. 15 N
Explanation: F = ma = 5 x 3 = 15 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.