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Author Question: In a physical fitness program, a woman who weighs 510 N runs up four flights of stairs in 22 s. Each ... (Read 428 times)

leilurhhh

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In a physical fitness program, a woman who weighs 510 N runs up four flights of stairs in 22 s. Each flight rises 3.1 m. (1 hp = 746 W)
 
  (a) What is her total change in potential energy?
  (b) What was the minimum average power (in watts) that she expended during the 22 s?
  (c) What horsepower motor would be required to generate the same power?

Question 2

A steel wire, 3.2 m long, has a diameter of 1.2 mm. The wire stretches 1.6 mm when it bears a load. Young's modulus for steel is 2.0  1011 Pa. The mass of the load is closest to
 
  A) 28 kg. B) 24 kg. C) 16 kg. D) 20 kg. E) 12 kg.



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nathang24

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Answer to Question 1

(a) 6.3 kJ (b) 290 W (c) 0.39 hp

Answer to Question 2

E





 

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