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# 1) A body constrained to move along the z-axis of a coordinate system is subjected to a constant force given by, F = - i cap + j cap +3 k cap N, where i

cap, j cap, k cap are unit vectors along the x, y, z- axis of the system, respectively. Which is the work done by this force in moving the body a distance of 4 m along the z -axis ? (answer should come 12 Joules)

2) A body is thrown on a rough surface such that friction force acting on it is linearly varying with distance travelled by it as f = ax + b. Find the work done by the friction on the box if before coming to rest the box travels a distance s. (answer should come )

3) You are re-shelving books in library. You lift a book from the floor to the top shelf. This kinetic energy of the book on the floor was zero and the kinetic energy of the book on the to shelf is zero, so no change occurs in the kinetic energy yet you did some work in lifting the book. Is the work-kinetic energy theorem violated? (answer should come -- there is no violation, total work on the book is zero.)
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by alwaz