C Exercise 11.5 Part A A student ate a Thanksgiving dinner that totaled 2900 Cal
ID: 1499489 • Letter: C
Question
C Exercise 11.5 Part A A student ate a Thanksgiving dinner that totaled 2900 Cal. He wants to use up all that energy by lifting a 18- kg mass a distance of 1.0 m. Assume that he lifts the mass with constant velocity and no work is required in lowering the mass. How many times must he lift the mass? Express your answer using two significant figures. My Answers Give Up Part B If he canand lower the mass once every 60 s , how long does this ex erase take? Express your answer using two significant figures. Search the web and Windows EndExplanation / Answer
11.5
A)
W = work done in lifting energy gained = mgh = 18 x 9.8 x 1 = 176.4 J
Total energy to be consumed = E = 2900 cal = 2900 x 4.18 = 12122 J
N = number of times lifted = E/W = 12122/176.4 = 68.72
B)
T = Time period = 6 sec
t = NT = 68 x 6 = 408 sec
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