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{20) A 23-kg stone suspended from a 36-m-long vertical cord is moving In a circu

ID: 1351561 • Letter: #

Question

{20) A 23-kg stone suspended from a 36-m-long vertical cord is moving In a circular are at 12 m/s. (a) What is the tension in the cord? (b) What is the maximum height the stone will reach? (c) An identical stone is suspended from a cord under the same tension in an elevator accelerating upward from rest. How high in cm will it rise in 0.1 sec? ANS: cm ? The answer to the same question about the stone swinging in the circular arc above would be (almost the same I much greater I much loss) ? Suppose instead the cord shown above breaks, and sketch the stone's subsequent path in the diagram.

Explanation / Answer

tension in the cord = mg + mv^2 / r

tension in the cord = 2.5 * 9.8 + 2.5 * 12^2 / 36

tension in the cord = 34.5 N

by conservation of energy

initial energy = final energy

0.5 * mv^2 = mgh

0.5 * v^2 = gh

0.5 * 12^2 = 9.8 * h

maximum height the stone will reach h = 7.3469 m