Overview
This lecture explains how to convert a speed from miles per hour to nanometers per second using step-by-step unit conversions.
Step 1: Convert Miles to Nanometers
- Start with the given value: 55 miles per hour (mi/hr).
- Use a conversion factor to change miles to meters (1 mile = 1,609.34 meters).
- Use a second conversion factor to change meters to nanometers (1 meter = 1,000,000,000 nanometers).
- Set up the calculation so that units cancel: miles cancel with miles, then meters cancel with meters, leaving nanometers.
Step 2: Convert Hours to Seconds
- Use a conversion factor to change hours to minutes (1 hour = 60 minutes).
- Use another conversion factor to change minutes to seconds (1 minute = 60 seconds).
- Cancel units: hours cancel with hours, then minutes cancel with minutes, leaving seconds.
Calculation Process
- Multiply numerators and denominators straight across using the chosen conversion factors.
- After both steps, the result is in nanometers per second (nm/s).
- Round the final answer to match the significant figures in the original value (2 significant figures for 55).
Key Terms & Definitions
- Conversion factor — a ratio used to convert from one unit to another.
- Significant figures (sig figs) — digits that carry meaning for precision in a number.
- Nanometer (nm) — one-billionth of a meter (1 m = 1×10⁹ nm).
Action Items / Next Steps
- Practice additional unit conversion problems for better understanding.
- Review examples similar to this problem as suggested.