Experimental Skills And Graphing Motion Flashcards
Independent variable
A variable that is deliberately changed (e.g, time)
X axis of graph
What is a variable?
Variables are quantities that change in an experiment
Dependent variable
A variable that changes in response to the independent variable
(Y-axis of graph)
How to label axis
Units must be given in brackets
If a quantity is raised to some power, then the units are raised to the same power
What if the line is straight?
The relationship between the variables is linear
E.g, y variable is linearly dependent on x variable
What if the line is straight and goes through (0,0)?
There is a proportional relationship
E.g, y variable is proportional to x variable
Y=mx + c
What is m and c?
M is the slope, c is the y intercept
How to calculate the slope?
M = (y2-y1)/(x2-x1)
Choose one point as either (0,0) or y or x intercept
Never choose data points
Indicate these points on the graph
Gives units of the gradient (y step unit / x step unit)
How to find y intercept if it is not on the graph?
(Y variable - y1 / x variable - x1) = slope
Rearrange till you have y on one side, and then you will have the equation on the other side
What is a random error?
It is an error that has an equal chance of being too high or too low
This affects the precision
What is a systematic error?
It is a constant error, where all values are either all too high, or all too low
Tis affects the accuracy
What is precision?
It relates to the variation of the values
What is accuracy?
It is how close your experimental value is to the actual value
How to find percentage error?
(Experimental value - actual value) / (actual value) x100
How to find of significant figures when multiplying and dividing?
Round the result to the number of significant figures as the number with the smaller significant figures in the calculation
