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Question Details - mass x gravity so you can write: F = ma...

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Question Details: You drop a 2.00 kg book to a friend who stands on the ground at distance D = 10.0 m below. Your friend's outstretched hands are at distance d = 1.20 m above the ground (Fig. 8-29). (a) What is the speed of the book when it reaches her hands? (b) If we substituted a second book with twice the mass, what would its speed be when it reaches her hands? (c) If, instead, the book were thrown down with initial speed 5.70 m/s, what would be the answer to (a) ? Response Details: (a) s = 10meters v(initial) = 0m/s v(final) = ? a = 9.8m/s 2 (assume down is positive) v(final) 2 = v(initial) 2 +2as v(final) 2 = 0 2 +2(9.8)(10) v(final) = 14 m/s (b) same v(final) as in part (a) as changing mass of an object does not change velocity proof: F = mass x acceleration (Newton's second law) force on an object falling is F =
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Unformatted text preview: mass x gravity so you can write: F = ma mass x gravity = mass x acceleration now mass will cancel out from both side gravity = acceleration hence acceleration (change is velocity) does not depend on mass (c) s = 10meters v(initial) = 5.70m/s v(final) = ? a = 9.8m/s 2 (assume down is positive) v(final) 2 = v(initial) 2 +2as v(final) 2 = 5.70 2 +2(9.8)(10) v(final) = 15.1158857 m/s Response Details: Note: For this problem, we will use conservation of energy (a) Note: The mass of the book does not matter when using energy conservation, thus, it cancels out Note: The initial kinetic energy is zero because it was dropped (b) As stated previously in part (a), the mass of the book does not matter, thus, its speed would be the same as it was in part (a) (c)...
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This note was uploaded on 01/13/2010 for the course ABC BTUN80809 taught by Professor Mr.chuck during the Spring '09 term at McGill.

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Question Details - mass x gravity so you can write: F = ma...

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