Section 8.12 Energy Analysis
Subsubsection Key Ideas
In Force Analysis for a Single System, you saw a strategy for force analysis. Approaching a context from an energy perspective follows a similar structure, but the goals are often different.
Energy Analysis.
-
Identify a system and choose a reference frame
-
Identify all forms of energy in the system
-
Determine the net external work on the system
-
Use the Work-Energy Theorem to relate change in energy and work
-
Check that your answers make sense
Sensemaking Strategy 8.12.2. Solve Multiple Ways.
Many problems in physics can be solved multiple ways. Since both ways should result in the same answer, this can be a strong confirmation that an answer is correct. Often, Force Analysis and Energy Analysis provide two distinct ways of solving a problem.
Subsubsection Activities
A*R*C*S 8.12.1. Pulling a Box.
In Practice Calculating Work, you considered the situation of pulling a box across a flat, level floor using a rope that makes an angle to the horizontal. Assuming you know the tension in the rope, find the speed of the box after it has traveled across the room.
