Mechanics: Work, Energy and Power
Work, Energy and Power: Audio Guided Solution
Pete Zaria works on weekends at Barnaby's Pizza Parlor. His primary responsibility is to fill drink orders for customers. He fills a pitcher full of Cola, places it on the counter top and gives the 2.6-kg pitcher a 8.8 N forward push over a distance of 48 cm to send it to a customer at the end of the counter. The coefficient of friction between the pitcher and the counter top is 0.28.
a. Determine the work done by Pete on the pitcher during the 48 cm push.
b. Determine the work done by friction upon the pitcher .
c. Determine the total work done upon the pitcher .
d. Determine the kinetic energy of the pitcher when Pete is done pushing it.
e. Determine the speed of the pitcher when Pete is done pushing it.
Audio Guided Solution
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b. -3.4 J
c. 0.8 J
d. 0.8 J
e. 0.8 m/s
Habits of an Effective Problem Solver
- Read the problem carefully and develop a mental picture of the physical situation. If necessary, sketch a simple diagram of the physical situation to help you visualize it.
- Identify the known and unknown quantities in an organized manner. Equate given values to the symbols used to represent the corresponding quantity - e.g., vo = 0 m/s; a = 4.2 m/s/s; vf = 22.9 m/s; d = ???.
- Use physics formulas and conceptual reasoning to plot a strategy for solving for the unknown quantity.
- Identify the appropriate formula(s) to use.
- Perform substitutions and algebraic manipulations in order to solve for the unknown quantity.
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