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A skater holds her arms outstretched as she spins at 130 rpm. What is the speed of her hands if they are 130 cm apart?

a) 130 cm/s
b) 260 cm/s
c) 390 cm/s
d) 520 cm/s

User Nisaa
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1 Answer

5 votes

Final answer:

The speed of a skater's outstretched hands while spinning at 130 rpm (with hands 130 cm apart) is approximately 884 cm/s, but this value does not match any of the provided options, indicating a potential issue with the question.

Step-by-step explanation:

The question concerns the calculation of the speed of a figure skater's hands while in a spinning motion. Assuming a skater spins at 130 revolutions per minute (rpm), we need to convert this to angular velocity in radians per second. Since 130 rpm is equivalent to 13.6 radians/second (because 1 rpm = 2π/60 radians/second), and the distance of each hand from the axis of rotation is 65 cm (130 cm apart), we can calculate the speed using the formula speed = angular velocity × radius.

To find her hands' speed, we multiply the angular velocity by the radius of one arm (half the total distance between them):

  • Speed = 13.6 radians/second × 0.65 meters,
  • Speed ≈ 8.84 m/s,
  • Speed ≈ 884 cm/s (since 1 m = 100 cm).

However, since none of the given answer options (a) 130 cm/s, (b) 260 cm/s, (c) 390 cm/s, (d) 520 cm/s) match the calculated speed of 884 cm/s, there may be an error in the question or the provided options. If forced to choose the closest correct answer, option (d) 520 cm/s would be the closest to the calculated speed, albeit it is still not correct.

User Jay Zamsol
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