Answer: 60 N s.
- A 20 N s
- B 60 N s
- C 40 N s
- D 80 N s
Correct answer: B. 60 N s
Explanation: Impulse = force × time = 20 × 3 = 60 N s (equal to the change in momentum).
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.