Newton's third law pair of forces always
Correct answer: B. act on two different bodies, so they never cancel each other
- A. act on the same body and therefore cancel
- B. act on two different bodies, so they never cancel each other
- C. are unequal in magnitude
- D. act in the same direction
Explanation
Action and reaction are equal and opposite but act on different objects, which is why a book on a table is held up by the table's push rather than by any cancellation. If they acted on one body nothing could ever accelerate. The weight of the book and the table's normal force are not a third law pair, though they happen to be equal here.
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About Newton's Laws of Motion
Newton’s laws explain inertia, the relation between net force and acceleration, and action-reaction pairs. Questions involve free-body diagrams, balanced and unbalanced forces, F = ma, force as the rate of change of momentum, and identifying genuine third-law pairs, which act on different bodies.
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