Mechanics: Work and Energy
Work and Energy: Audio Guided Solution
Extra Problem 4:
A 168-gram baseball is moving with a kinetic energy of 43.4 Joules and a potential energy of 49.7 Joules at one location in its trajectory. If the effect of air resistance on the baseball can be ignored, then what is its kinetic energy (in Joules) the instant prior to striking the ground?
Audio Guided Solution
Use the equation below to solve this problem. Cancel terms, substitute and solve.
KEi + PEi + Wnc = KEf + PEf
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Habits of an Effective Problem Solver
An effective problem solver by habit approaches a physics problem in a manner that reflects a collection of disciplined habits. An effective problem-solver...
- ...reads the problem carefully and develops a mental picture of the physical situation. If needed, they sketch a simple diagram of the physical situation to help visualize it.
- ...identifies the known and unknown quantities in an organized manner, often times recording them on the diagram iteself. They 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 = ???).
- ...plots a strategy for solving for the unknown quantity; the strategy will typically center around the use of physics equations be heavily dependent upon an understaning of physics principles.
- ...identifies the appropriate formula(s) to use, often times writing them down. Where needed, they perform the needed conversion of quantities into the proper unit.
- ...performs substitutions and algebraic manipulations in order to solve for the unknown quantity.