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Get Full Access to University Physics - 13 Edition - Chapter 7 - Problem 3e
Get Full Access to University Physics - 13 Edition - Chapter 7 - Problem 3e

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# CP A 90.0-kg mail bag hangs by a vertical rope 3.5 m long. ISBN: 9780321675460 31

## Solution for problem 3E Chapter 7

University Physics | 13th Edition

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Problem 3E

CP? A 90.0-kg mail bag hangs by a vertical rope 3.5 m long. A postal worker then displaces the bag to a position 2.0 m sideways from its original position, always keeping the rope taut. (a) What horizontal force is necessary to hold the bag in the new position? (b) As the bag is moved to this position, how much work is done (i) by the rope and (ii) by the worker?

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Solution 3E To solve this question, let us have a look at the figure below where various forces and their components are shown for the system. Let the tension in the rope is T and acts as shows above. From the figure, sin x = 3.5 x = sin 1(2.0) 3.5 0 x = 34.7 Also, the horizontal force F H = Tsin x…..(1) Weight of the bag mg = Tcos x…..(2) (a) Dividing equation (1) by (2), F H mg = tan x F = mgtan x H F = 90.0 kg × 9.80 m/s × tan 34.7 0 H F H = 611 N Therefore, the approximate value of the horizontal force is 611 N. 0 (b) The height moved by the bag is = 3.5 3.5cos x = 3.5 3.5cos 34.7 = 0.62 m 2 Work done by the worker is = 0.62 m × 90 kg × 9.8 0m/s = 547 N The approximate work done by the worker is 547 N. The rope itself cannot change its position unless a force is applied on it. Therefore, work done by the rope is zero.

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##### ISBN: 9780321675460

University Physics was written by and is associated to the ISBN: 9780321675460. The full step-by-step solution to problem: 3E from chapter: 7 was answered by , our top Physics solution expert on 05/06/17, 06:07PM. Since the solution to 3E from 7 chapter was answered, more than 777 students have viewed the full step-by-step answer. The answer to “CP? A 90.0-kg mail bag hangs by a vertical rope 3.5 m long. A postal worker then displaces the bag to a position 2.0 m sideways from its original position, always keeping the rope taut. (a) What horizontal force is necessary to hold the bag in the new position? (b) As the bag is moved to this position, how much work is done (i) by the rope and (ii) by the worker?” is broken down into a number of easy to follow steps, and 72 words. This textbook survival guide was created for the textbook: University Physics, edition: 13. This full solution covers the following key subjects: position, bag, rope, Worker, moved. This expansive textbook survival guide covers 26 chapters, and 2929 solutions.

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