Mathematics
Grade Levels: 8th Grade, 9th Grade, 10th Grade, 11th Grade, 12th Grade,
Topics: AlgebraExpressions and Equations
Common Core State Standard: A-CED.2, A-CED.4,
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
Lesson:
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 three things:
a) the distance between you and the computer, L
b) the velocity of light traveling through the cable, v
c) the amount of time it takes the other computer to process your signal, tprocessing
The equation you would use to find the response time is this:
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.
1. Calculate tresponse for the given values of L and tprocessing:
| L | tprocessing | tresponse |
| 500,000 meters | 0.013 seconds | |
| 8,000,000 meters | 0.005 seconds | |
| 2,000 meters | 0.002 seconds | |
| 20,000,000 meters | 0.04 seconds |
2. Solve the equation to find the unknown value:
| L | tprocessing | tresponse |
| 750,000 | ? | 0.0325 |
| ? | 0.001 | 0.00195 |
| ? | 0.015 | 0.016 |
| 50,000,000 | ? | 0.503 |