Mechanics: Work and Energy

Work and Energy: Audio Guided Solution

Extra Problem 2:

A skier is moving along a plateau of a ski slope with a kinetic energy of 6376 Joules and a potential energy of 10752 Joules (relative to the bottom of the slope). If the skier has a kinetic energy of 22752 Joules at the bottom of the slope, then what quantity of work (in Joules) was done upon the skier by use of the poles? 

 




 

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.