Mechanics: Work, Energy and Power
Work, Energy and Power: Audio Guided Solution
Problem 30:
Gwen is baby-sitting for the Parker family. She takes 3-year old Allison to the neighborhood park and places her in the seat of the children's swing. Gwen pulls the 1.8-m long chain back to make a 26° angle with the vertical and lets 14-kg Allison (swing mass included) go. Assuming negligible friction and air resistance, determine Allison's speed at the lowest point in the trajectory.
Audio Guided Solution
Habits of an Effective Problem Solver
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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.
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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 = ???.
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Use physics formulas and conceptual reasoning to plot a strategy for solving for the unknown quantity.
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Identify the appropriate formula(s) to use.
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Perform substitutions and algebraic manipulations in order to solve for the unknown quantity.
Read About It!
Get more information on the topic of Work, Energy and Power at The Physics Classroom Tutorial.
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