qz3sol_3081sp10

# qz3sol_3081sp10 - force is W s = 9 J when the displacement...

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TA: Tomoyuki Nakayama Monday, February 8 th , 2010 PHY 2048: Physic 1, Discussion Section 3081 Quiz 3 (Homework Set #5) Name: UFID: Formula sheets are not allowed. Calculators are allowed. Do not store equations in your calculator. You need to show all of your work for full credit. ________________________________________________________________________________ A can of bolts and nuts is pushed 2.00 m along an x axis by a broom along the greasy (frictionless) floor of a car repair shop in a version of shuffleboard. Figure below gives the work W done on the can by the constant horizontal force from the broom, versus the can’s position x . The scale of the figure’s vertical axis is set by W s = 9.00 J. a) What is the magnitude of that force? According to the graph, the work done by the applied
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Unformatted text preview: force is W s = 9 J when the displacement is d = 2 m. The definition of work gives W s = Fd F = Ws/d = 4.50 N b) If the can was initially at rest and had a mass of 0.500 kg, what is its speed at the end of the 2.00 m? We apply the work-kinetic energy theorem to the can at x = 0 m and x = 2 m, express the kinetic energy in terms of mass and velocity, and solve the equation for the velocity. K = (1/2mv f 2 ) 0 = Ws v = (2Ws/m) = 6.00 m/s c) If the can had an initial kinetic energy of 5.00 J, moving in the positive direction of the x axis, what is its kinetic energy at the end of the 2.00 m? Now the initial kinetic energy is not zero. The work-kinetic energy theorem yields K = K f K i = W s K f = K i + W s = 14.0 J...
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