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Hello everyone.
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In this problem we're asked to calculate how much work gravity does on a book as we move it from a table onto a bookshelf and then we're asked how much work our hands or how much work we do on this book as we do the same process.
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So first of all, this is the situation that we have.
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So there's a table and there's a book sitting on it, which is this red block over here.
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The table has a height of h .t.
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And we're putting it onto a book.
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Bookshelf, which has a height of h .s.
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And i've taken the upper direction to be positive.
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We're told that the mass of the book is 2 kilograms.
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The height of the table is 0 .75 meters, and the height of the shelf is 2 .3 meters.
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We're also going to be using the acceleration due to gravity, which i have taken to be 9 .8 meters per second squared.
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Okay, so for the first part, we went to calculate the work done by gravity.
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And so we can notice that the displacement of the book is going to be in a positive direction, while the force of gravity is acting on the negative direction...