Exam-style question
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Which of the following best explains why torque is not simply F = ma?.
- A.Torque is a scalar, while F = ma is a vector equation.
- B.Torque involves a lever arm, whereas F = ma does not.
- C.F = ma only applies to rotating bodies.
- D.Torque is measured in newtons, whereas F = ma is measured in newton‑metres.
Model answer
What a good answer should say
- Torque involves a lever arm, whereas F = ma does not.
Explanation
Why this works
Define both: torque (τ) is the product of force and perpendicular distance from the axis; F = ma relates force to mass and linear acceleration. Identify key difference: torque includes the lever arm (distance) and direction, whereas F = ma lacks any distance term.
Explain when each applies: use τ when analysing turning effects about an axis; use F = ma for linear motion. Conclude: the presence of the lever arm distinguishes torque from the linear force equation.
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