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Unformatted text preview: Gozick, Brandon Homework 8 Due: Oct 6 2006, 5:00 pm Inst: D Weathers 1 This printout should have 11 questions. Multiplechoice questions may continue on the next column or page find all choices before answering. The due time is Central time. 001 (part 1 of 1) 10 points A cheerleader lifts his 24 kg partner straight up off the ground a distance of 0 . 268 m before releasing her. The acceleration of gravity is 9 . 8 m / s 2 . If he does this 11 times, how much work has he done? Correct answer: 693 . 37 J. Explanation: The work done in lifting the cheerleader once is W 1 = mg h = (24 kg)(9 . 8 m / s 2 )(0 . 268 m) = 63 . 0336 J . The work required to lift her n = 11 times is W = nW 1 = (11)(63 . 0336 J) = 693 . 37 J . keywords: 002 (part 1 of 1) 10 points A man cleaning his apartment pushes a vac uum cleaner with a force of magnitude 24 . 6 N. Theforcemakesanangleof16 . 2 withthehor izontal floor. The vacuum cleaner is pushed 2 . 01 m to the right along the floor. Calculate the work done by the 24 . 6 N force. Correct answer: 47 . 4827 J. Explanation: Using the definition of work, we have W = ~ F ~s = F s cos = (24 . 6 N)(2 . 01 m)cos16 . 2 = 47 . 4827 J . Note: The normal force N , the weight m~g , and the upward component of the applied force, (24 . 6 N)sin16 . 2 , does no work because they are perpendicular to the displacement. keywords: 003 (part 1 of 3) 0 points A cart loaded with bricks has a total mass of 9 . 3 kg and is pulled at constant speed by a rope. The rope is inclined at 21 . 2 above the horizontal and the cart moves 30 . 9 m on a horizontal floor. The coefficient of kinetic friction between ground and cart is 0 . 6 ....
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This note was uploaded on 09/12/2008 for the course PHYS 1710 taught by Professor Weathers during the Fall '08 term at North Texas.
 Fall '08
 Weathers
 mechanics, Work

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