Chapter 1 Flashcards
What is a hypothesis?
An educated guess about how something works. It is not supported by any significant amount of evidence. With consistent evidence a hypothesis may become a theory or a law.
What is a law?
A general statement of what happens, It describes a phenomenon of a pattern in nature.
What is a theory?
An explanation for why a law is true it explains the phenomenon. THEORIES NEVER BECOME LAW.
Precision
The degree of exactness of a measurment.
Accuracy
How close a measurment is to the real answer
Branches of Physics
Motion, properties of materials, sound, waves, light,ect.
Quantity
Type of thing being measured
Magnitude
Measurment of the number
Unit
What we measure Quantity in
What are the two types of units?
Base units and derived units
Base units
the standard units of measurement for the simplest quantities.
Derived Units
new names given to combinations of base units.
What are the three base units we use in the metric system?
Time- seconds
Length- meter
Mass - Kilogram
Why are abbreviations capitalized?
If they are named after a person
What is Gigajoules in scientific notation?
10^9 GJ
What is megahertz in scientific notation?
10^6 MHz
What is kilometers in scientific notation?
10^3 km
What is centimeters in scientific notation?
10^-2 cm
What is milliseconds in scientific notation?
10^-3 ms
What is micrograms in scientific notation?
10^-6 μg
How to convert units:
Multiply by a ratio that equals 1 which causes the original units to cancel out and the desired unit to remain.
Adding or subtracting numbers in scientific notation:
- Do any unit conversions
- add the expressions so that the exponents match
- Add or subtract the mantissas
- Adjust the exponent of the answer as necessary to ensure that the mantissa is between 1-10
Multiplying or dividing numbers in scientific notation:
Simply multiply or divide the mantissas and combine the exponents using the exponent laws.(units don’t need to match)
Significant figures
Indicates how precise a measurment is.
1. All non-zero didgits are significant
2. all final zeros after the decimal point are significant
3. All zeros between other signiicant digits are significant
4. Zeros whose only purpose is to indicate the position of the decimal point are not significant
How many sifnificant digits does a counted value have?
Infinite
Rounding with 5
Round down if it’s under 5. Round up if it’s above 5.
If it is 5 then round up when the next digit is odd or is a 0. Round down is the last digit is even.
Rounding within Math Operations and Sig. Figs.
Round the answer to the same number of sig figs as the factor with the fewest sig figs
Data Table
- Quantitiy, units and error go in the heading since the apply to all the measurements in the column.
- All the measurements within a column are expressed to the same precision.
Graphing Data - 1-3
- Title the graph in the form, “dependent variable vs. independent variable.”
- Label the axes with the quantity (type of measurement) and the units, but not the error.
- Sale the axis to fit the data - use as much of the whole page as you can, subject to the following guidlines. (Don’t draw broken axes. If the data range is far from zero, simply begin somewhere suitable other that zero)
Graphing Data - 4-5
- Plot the points on the graph and circle them so that they are easy to spot. do not label them with the data values
- If the data are linear or seem to follow a smooth curve, draw a best-fit line os curve.(Don’t connect the dots)
Interpolation:
Using the best-fit line to estimate values between extremes of the collected data points
Extrapolation:
Using the dotted best-fit line to estimate cales beyond the endpoints of the collected data.
How to calculate slope of the best-fit line:
(position 2 - position 1) /
(time 2 - time 1)
Linear relationship:
If the graph is a straight line. y=kx
Vertical = slope x horizontal
Direct relationship
if one quantity doubles so does the other.
Quadradic Relationship:
If the line curves. y=kx^2
Graph is a parabola (actually only half of one).
Inverse relationship:
If the line curves down the graph at the top.
y = k/x
If one quantity doubles the other is half as much.
This graph is a hyperbola.
Inverse square relationship:
Graph is very similar to the one for inverse relationship.
y = k/x^2
Proper problem solving format:
- Write down the given information as well and the unkown quantity, using the proper symbols and units
- Write the basic formula
- Rearrange the formula got the unkown quantity witht the unknown on the left side
- Subsitute data (inculding units)
- Solve and express the answer with the correct units and correct number of sig. figs.
