The angular speed of the second hand of a watch is:
Correct answer: C. (∏/30) rad/sec
- A. (∏/1800) rad/sec
- B. (∏/60) rad/sec
- C. (∏/30) rad/sec
- D. (2n) rad/sec
Explanation
The correct answer is (π/30) rad/sec. The second hand of a watch completes one full revolution (2π radians) in 60 seconds, which means its angular speed is calculated as: Angular Speed = Total Rotation / Time = (2π radians) / (60 seconds) = (π/30) rad/sec. Let's examine the other options: (π/1800) rad/sec suggests an extremely slow speed that is not applicable to a watch's second hand, as it would imply a highly unrealistic time for a full rotation. (π/60) rad/sec is also incorrect because it does not accurately represent the complete rotation in the given time frame of 60 seconds. (2n) rad/sec is completely irrelevant, as 'n' is not defined and does not pertain to the angular motion of the second hand.
This question appeared on the KMU MDCAT 2023 paper, which you can sit online with every answer explained.
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Angular velocity describes how quickly angular displacement changes with time, with ω = Δθ/Δt and units of radians per second. Questions relate angular and linear motion through v = rω, use the direction given by the right hand rule, and distinguish angular velocity from angular acceleration and ordinary frequency.
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