A stone of mass 250g is tied to the end of a string of length 1.0m. It is whirled in a horizontal circle with a frequency of 30rev/min. What is the tension in the string ?
Correct answer: A. π2/4N
- A. π2/4N
- B. π2N
- C. π2/2N
- D. 2π2N
Explanation
Option A is correct.To calculate tension, we use the formula Tension = force x extension, which can also be written as m x l x w2.First, we convert 30 revolutions/minute into seconds, so 30/60 = 1/2 revolution per second.Then we use this formula: m x l x w2so Tension = 250 / 100 x 1 x (2 x π x 1/2)2Tension = 1/4 x 1 x (π )2The unit for tension is Newton (N), so option A is correct.
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