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A 0.80-kg book moves verticallyupward a distance of 17 m, andthen vertically dow

ID: 1671480 • Letter: A

Question

A 0.80-kg book moves verticallyupward a distance of 17 m, andthen vertically downward 17 m,returning to its initial position. (a) How much work is done by gravity during the upward motion ofthe book?
J

(b) How much work is done by gravity during the downward motion ofthe book?
J

(c) What is the total work done on the book by gravity during thecomplete round trip?
J

(d) On the basis of your answer to part (c), would you say that thegravitational force is conservative or nonconservative? Explainyour answer (a) How much work is done by gravity during the upward motion ofthe book?
J

(b) How much work is done by gravity during the downward motion ofthe book?
J

(c) What is the total work done on the book by gravity during thecomplete round trip?
J

(d) On the basis of your answer to part (c), would you say that thegravitational force is conservative or nonconservative? Explainyour answer

Explanation / Answer

Mass m = 0.8 kg

Accleration due to gravity g = 9.8 m/ s ^ 2

Vertical distance S = 17 m

(a) work is done by gravity during the upward motion of the bookW = -mgS

                                                                                                           = -133.28 J

Since weight and displacement are opposite to each other



(b) work is done by gravity during the downward motion of the bookW ‘ = mgS = 133.28 J

Both weight and displacement are in samedirection  


(c) the total work done on the book by gravity during the completeround trip = W + W’ = 0 J