Physics Quiz: SI Units and Metrics

Study Notes

The metric system has a prefix system to represent large and small quantities:
- Giga- means 10^9
- Micro- means 10^-6
- Nano- means 10^-9
There are 7 base units in the SI system:
- meter (m)
- kilogram (kg)
- second (s)
- electric charge (not specified)
- Kelvin (not specified)
- mole (not specified)
- candela (not specified)

Unit conversion is necessary to ensure proper calculations
Ways to ensure proper unit conversion:
- Work in the same system of units
- Use unit analysis
- Check units before solving an equation
Example: 1 kg = 2.2 lb means 1 kg is equivalent to 2.2 lb

Unit analysis is a way to check if an equation is dimensionally correct
It involves checking if the units on both sides of an equation are equal
Unit analysis cannot tell if an equation is physically correct or numerically correct
Example: A = pr^2 and A = pd^2/2 can be checked using unit analysis to determine which is correct

Significant figures are a way to represent the accuracy of a measurement
Rules for significant figures:
- Non-zero digits are always significant
- Zeros between non-zero digits are always significant
- Leading zeros are never significant
- Trailing zeros are only significant if the number contains a decimal point
Example: 103.07 has 5 significant figures, 124.5 has 4 significant figures, 0.09916 has 5 significant figures, and 5.408 * 10^5 has 5 significant figures

Steps in problem solving:
- Read the problem carefully
- Check units and significant figures
- Perform calculations
- Check if the answer is reasonable
Importance of unit analysis and significant figures in problem solving
Example: Calculating the surface area of a can and the volume of water in a pool