When a wheel 1 m in diameter makes 30 rev min the linear speed of the point on its rim in ms-1 is_______________?
Correct answer: B. π/2
- A. 2π
- B. π/2
- C. π
- D. 20π
Explanation
The wheel's circumference is πd = π x 1 m = π m, and 30 revolutions per minute equals 0.5 revolutions per second. Therefore, linear speed = 0.5 x π m/s = π/2 m/s. The likely mistake is choosing π, which comes from using 1 revolution per second instead of 0.5 revolution per second.
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