Answer: Newton's third law.
- A Newton's first law
- B Newton's second law
- C Newton's third law
- D Law of gravity
Correct answer: C. Newton's third law
Explanation: Bullet moves forward; gun recoils backward. Equal and opposite forces: Newton's third law.
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.