Welcome Patriot Physics Scholars

“Fate rarely calls upon us at a moment of our choosing.”

Convert the following: um = ___________ hm Mm = __________ km kg/m 3 = ________kg/L 4.45 km/hr = _________m/s 5.35 m 2 = __________cm 2 Scientific Notation Problems: x x x 10 6 x 2.1 x (1.2 x 10 3 )(7.6 x 10 4 )/(5.8 x )

1. Recognize types of relationships among variables and find and interpret the slope of a line. 2. Determine dependent and independent variables, graph data points, calculate the slope and interpret questions using a graph. 3. Collect and record data using basic measuring tools. 4. Identify uncertainties as error bars in graphs. 5. State random uncertainty as an uncertainty range (+) and represent it graphically as an error bar. 6. Determine the uncertainties in the slope and intercepts of a straight line graph.

When should I draw a curve …? …and when should I draw a line-graph ?

Data Presentation Determine the independent variable, dependent variable, and the derived quantity for the activity. Make a table containing vertical columns for the independent variable, dependent variable, and the derived quantity and label them appropriately. Subdivide the column for the dependent variable to reflect the number of trials. See below for an example data table. Calculate the derived quantities and enter the values into the table.

Column for the Independent Variable ? Column for the Dependent Variable ? Column for the Derived Quantity ? Trials 12345

1. Choose simple scales. For example: 1 large square = 1 newton (1 N) or 1 large square = 2 N, or 5 N, or 10 N But never choose an awkward scale, like 1 square = 3 N or 7 N Choose a scale that will make your graph use most of the sheet of paper.

Put the dependent variable on the ‘y-axis’ and the independent variable on the ‘x-axis’

Plot the points neatly. o o o o o o Re-check each one before your next step. Usually you need 5 or more points for the graph. To mark the points we usually use a

If the points form a straight line… …draw the best straight line through them... Called the “line of best fit”. o o o o o o ‘line of best fit’

If the points form a curve… …draw a free-hand curve of best fit Do not join the points like a ‘dot-to-dot’.

If a point is not on the line… …use your apparatus to check this measurement again You can decide to ignore anomalous points. This is called an anomalous point. o o o o o o

The equation for a line (constant direct relationship): y = mx + b where m = slope = rise/run b = y-intercept

the current in a resistor against the p.d. across it. current voltage This illustrates Ohm’s Law.

The equation for a parabola (changing direct relationship): k – constant The equation for hyperbola (inverse relationship):

A curved graph, rising : The dependent variable rises quickly at first and then more slowly Here are some examples:

the velocity of a falling object against the time. velocity time Eventually the object will reach its terminal velocity.

A curved graph, falling : The dependent variable falls quickly at first and then more slowly

the activity of a radioactive source against the time. activity time The time to fall to half is called the half-life.

Draw and label the axes of the graph on the graph paper. Determine the axes for the independent variable and dependent variable and choose an appropriate scale for the X-axis and Y-axis. Use the whole sheet of graph paper, make the graph large! Plot the data points on the graph. DO NOT CONNECT THE DOTS! Draw a line of best fit that summarize the data and write a descriptive sentence. (What is the relationship between the variables?)

A solar powered car designed by the Patriot Physics Club is racing in the County Championships. The car travels the course of 80 m in a time of 16 seconds. The interval times and the distance traveled were measured and recorded below Time (s) Distance (m)

a. Plot a graph of the solar power car’s distance and time on graph paper, follow proper graphing procedure. b. What is the relationship between the two variables? c. Determine the slope of the graph. d. What does the slope represent?

Tom is playing with a hot wheels car during lunch. He begins to calculate the time and final velocity of the car as it travels down a 50 cm ramp. The ramp is held at a constant angle and once Dave gives the car an initial velocity it accelerates at a constant rate. Here is the data Dave collected. a. Plot a graph of the solar power car’s distance and time on graph paper, follow proper graphing procedure. b. What is the relationship between the two variables? c. Determine the slope of the graph. d. What does the slope represent? Time seconds Average Velocity (m/s)

It is Monday morning and 7:30; you are on your way to school driving down Rte. 66 at 15 m/sec. You realize that you might be late so you continually increase your speed until you reach 60 m/sec. Below are the values for the speed you were traveling over the 16 seconds you changed your speed. Time Speed (seconds)m/sec)(seconds)(m/sec) a. Plot a graph of your speeds vs. time on the graph paper on the back, follow proper graphing procedure. b. What is the relationship between the two variables? c. Calculate the slope of the graph. d. What does the slope represent?

Have a great Day Physics Scholars!