Response Time

If you send a signal over a fiber optic cable to another computer and get a response, the response time (tresponse) depends on the distance between you and the computer (L) and the velocity of light traveling through the cable (v) as well as the amount of time it takes the other computer to process your signal (tprocessing) according to this equation:

Response Equation

Note that the velocity of light in fiber optic cable (v) is about 2/3 of the velocity of light in a vacuum, which makes it approximately equal to 200,000,000 meters/second.

Solve the above equation for unknowns.

Subject: Mathematics
Topics: Algebra—Expressions and Equations
Grades: 8 - 12
Knowledge and Skills:
- Can evaluate expressions by substituting values for variables
- Can simplify expressions using correct order of operations
- Can do basic operations on both sides of an equation in such a way as to preserve the equality

Download Teacher Guide: Response Time (PDF)
Download Student Lesson: Response Time (PDF)

Communication at the Speed of LightCommunication at the Speed of Light:

Tiny glass filaments carry so much information that all the books ever written could be transmitted over a single fiber optic cable in a few seconds. This technology is at the heart of 21st century communications systems.
Running time 1:44 minutes.

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