Link to Unit 0 Notes
Scientific Notation
Unit Conversions
Scientific Notation
- Used to represent really big and really small numbers
- The E on the calculator means *10^ (the number after the E)
- NEVER write the E when showing your work
Unit Conversions
- If you put a certain unit both above the fraction and below the fraction, they will cancel out
- Use known relationships between units (60 seconds = 1 minute or 1 inch= 2.54 centimeters) to find answers
Math With Units
- Always convert to the same units for addition and subtraction
- You can multiply or divide with different dimensions (might end up with ft^2 or m/s)
- ALWAYS WRITE YOUR FINAL ANSWER WITH UNITS!!!
Practice Problem (from Fundamentals Packet)
Which of the following are valid expressions?
a) 4.2 hours + 1.2 hours + 2.2 hours - VALID because units are consistent = 7.6 hours
b) 9.0 dollars/yard + 3 yards - INVALID because you can't add with different dimensions
c) 9.0 dollars/yard * 3 yards + $2 - VALID because the yards cancel out when you multiply 9.0 $/yard and 3 yards, which makes the units dollars which you can add to $2 = $29
d) 18 feet + 6 inches - VALID WITH UNIT CONVERSION (you just have to convert 18 feet into inches) = 222 inches
Interpreting Graphs
- Points- Always give us a prediction of our dependent variable for a specific value of the independent variable
- Slope- Aways tells us how the dependent variable changes (increases/decreases) as we increase the independent variable
- This might not always be constant!!!
- Y-intercept- Always tells us about the value of the dependent variable when the independent variable = 0
Different Types of Graphs
- Linear- Constant slope
- Quadratic and Inverse- Changing slope
- Flat line- Slope of 0
Determining Confidence
Sources of Uncertainty
- Lots of data (5-10 data points)
- Large range (largest value should be 10x the smallest value)
- Multiple trials (3-5 trials)
Sources of Uncertainty
- Reaction time
- Parallax shift (different angle affects perception and measurements)
- Equipment
- NEVER SAY HUMAN ERROR!