Chapter 1: Basic Training

Physics – The study of the physical world.

How to solve physics problems:Step 1: Write the knowns and unknowns.

Step 2: Write equations

Step 3: Solve

Step 4: Evaluate: Correct Units / Make Sense

SI UnitsSI is French for Systeme International d'Unites

7 base units. All others are derived from these 7.

Dimensional AnalysisFancy word for converting between units.

Example: Convert 43 km/h to m/s.

Step 1: Write down what you’re given.

Step 2: Make sure units on top match one on bottom

Step 3: Cancel out units until you arrive at desired units.

Step 4: Does it make sense?

How many kilometers in a meter?

How many grams in a megagram?

How many fs are 4,000,000 μs?

If you have 4.6 E 3 milliamps, how many kiloamps is that?

How many inches are in 4 miles?

How many seconds are in a year?

How many .mp3 files will fit on a 30 GB iPod? Assume the average .mp3 file is 3 KB.

Significant FiguresAll non-zero digits are significant.

1234 4.56

ZEROS:Zeros between two sig. figs. are significant.

3004 2.0005 4050607

Zeros as placeholders are NOT significant.

0.0004 0.0606 5,000,900 4.5 x 103

Zeros on the far right of a decimal number are significant.

4,000.00 0.00300 456.00970 4.50 E 3

Sig. Fig. ArithmeticAddition / Subtraction: The answer has to have the same number

of places to the RIGHT OF THE DECIMAL as the least of the measurements.

7.02 + 3.1 – 4.555 + 10

Multiplication / Division: The answer has to have the same number of TOTAL significant figures as the least of the measurements.

5.6 x 4.03 x 0.40

MeasurementsMeasurement: A comparison between an unknown quantity and

a known standard.

Precision vs. Accuracy.Precision: How close measurements agree.

Accuracy: How close measurements are to accepted value

Graphing

Dependent Variable

Factor that ‘depends’ upon the independent variable. Usually the variable that fluctuates without any pattern.

Independent Variable

The factor which is manipulated or controlled during the experiment. Often it is the variable that goes up incrementally.

3 Major Types of Relationships in Graphing

Linear Relationship Quadratic Relationship Inverse Relationship

A relationship where the line of best fit is a straight line.

y = mx + b

A relationship where the line of best fit is a parabola.

y = ax2 + bx + c

A relationship where the line of best fit is a hyperbola.

y = a / x

Finding Lines of Best Fit w/ Calculator Step 1: Entering the data into the calculator.

STAT → Edit → (put in x values in L1 , and put y values in L2)

To clear an entire list, get to the edit screen, highlight L1 and push ‘Clear’.

Step 2: Graphing your data.2nd → Y= → Enter → Highlight the On and push Enter → Zoom → ZoomStat → Enter

Step 3: Calculating the Line of Best Fit.

x values y values

First decide what type of a relationship it is: Linear, Quadratic, Inverse (aka logarithmic or ln)

STAT → arrow to the right over CALC → arrow down and select which type of regression it is to perform QuadReg, LinReg, LnReg → then hit 2nd → 1 (or the L1) → comma (right above the 7 key) → 2nd → 2 (or the L2) → ENTER

Step 4: Graphing the Line of Best Fit Over the Data

Hit the Y= key and enter in the equation it gave you in step 3.

Finding Lines of Best Fit w/ MS ExcelStep 1: Entering the data into the computer.

Step 2: Making the chart.

Click ‘Insert’ → Chart → select which type of chart you want → Next → select the ‘Series’ tab → If there is anything in window 1 delete it → Add → Click the X Values button → highlight your X values → Enter → Click the Y Values button → highlight your Y values → Enter → Click Next and Follow Prompts or Finish

Window 1 X Values Button

Y Values Button

Step 3: Adding a Line of Best Fit to Chart.

Click anywhere in the chart → Click the ‘Chart’ tab at top → Add Trend Line → Select the type which suits your data → Click the ‘Options’ tab → select the box at the bottom which says ‘Display Equation on Chart’. → Done.

Find the equation of the line of best fit for each of the sets of the data below. Mass (kg) Spring Length (cm) Current (mA) Resistance (Ω) Time (hr) Distance (m)

0 13.7 5 24.0 0.4 1.05 14.1 10 12.1 0.8 3.1

10 14.5 15 7.5 1.2 7.115 14.9 20 6.1 1.6 12.220 15.3 25 5.0 2.0 19.825 15.7 30 4.830 16.0 35 4.535 16.4 40 3.7

45 3.650 3.555 3.5

Link to MS Excell File