Answer: Inertia.
- A Acceleration
- B Inertia
- C Action-Reaction
- D Momentum
Correct answer: B. Inertia
Explanation: Newton's first law states that a body resists changes in its state of motion: this resistance is called inertia.
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.