HW9a - Version One Homework 9 savrasov 39822 This print-out...

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Version One – Homework 9 – savrasov – 39822 – Nov 13, 2007 1 This print-out should have 8 questions. Multiple-choice questions may continue on the next column or page – fnd all choices beFore answering. The due time is Central time. Sphere Held Against a Wall 01 12:01, trigonometry, numeric, > 1 min, fxed. 001 (part 1 oF 3) 1 points A solid sphere oF radius R and mass M is held against a wall by a string being pulled at an angle θ . f is the magnitude oF the Frictional Force and W = M g . W P F θ R Towhatdoesthetorqueequation X i ~ τ i = 0 about point O (the center oF the sphere) lead? 1. F = f correct 2. F + W = f 3. F cos 2 θ = f 4. F sin θ = f 5. F sin θ cos θ = f 6. W = f Explanation: W P F θ R R f Applying rotational equilibrium about O , the center oF the sphere, X i ~ τ i = 0i, so τ c = τ cc F R = f R F = f . 002 (part 2 oF 3) 1 points To what does the vertical component oF the Force equation lead? 1. F sin θ + f = W correct 2. F sin θ = W 3. F cos θ + W = f 4. F sin θ = f 5. F sin θ = f + W Explanation: Applying translational equilibrium verti- cally, X i F yi = F sin θ + f -W = 0 F sin θ + f = W . 003 (part 3 oF 3) 1 points ±ind the smallest coe²cient oF Friction μ needed For the wall to keep the sphere From slipping. 1. μ = 1 cos θ correct

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Version One – Homework 9 – savrasov – 39822 – Nov 13, 2007 2 2. μ = sin θ 3. μ = cos θ 4. μ = tan θ 5. μ = 1 sin θ 6. μ = 1 tan θ Explanation: Let N be the normal force. f μ N ; when
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This note was uploaded on 01/10/2010 for the course PHY na taught by Professor Richardscalettar during the Fall '09 term at UC Davis.

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HW9a - Version One Homework 9 savrasov 39822 This print-out...

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