PHYSICS CHAPTER 1 Notessection 1-1 to 1-3

Mrs. AcordHonors Physics

PHYSICS CHAPTER 1 NOTESSection 1-1 to 1-3

A good understanding of ______makes it possible to critically examine scientific theories and make educated decisions about science-related issues facing our society.

The goal of physics is to use a small number of basic concepts, equations, and assumptions to describe the ______world - to discover the essential nature of matter and energy and the relationship between them.

Any problem that deals with temperature, size, motion, position, shape or color involves physics.

Physics can be divided into the major divisions of: ______, thermodynamics, waves, optics, electromagnetism, relativity and quantum mechanics.

Mechanics is the study of ______and its causes.

Thermodynamics is the study of ______and temperature.

Electromagnetism is the study of electricity, magnetism, and light

The scientific method is used to try to explain how things work.

Steps of the Scientific Method

1. Make observations and collect ______that lead to a question.
2. Formulate and objectively test hypotheses by ______.

An hypothesis is a possible solution to a problem.

1. ______results, and revise the hypothesis if necessary.
2. State conclusions in a form that can be evaluated by others. A conclusion is valid only if it can be verified by other people.

When starting an investigation, a scientist collects known facts and then formulates hypotheses. From this, the scientist plans experiments, calculations, and observations to test the hypothesis or hypotheses. Once confirmed, an hypothesis is incorporated into theories or ______

ex. In 1609, Kepler hypothesized that all the planets have elliptical orbits. Once confirmed, this hypothesis became part of Kepler's laws of planetary motion.

A law is a statement that describes a natural phenomenon. It may be stated in words or as a mathematical ______.

ex. Newton's second law of motion in words: The effect of an applied force is to cause the body to accelerate in the direction of the force. The acceleration is in direct proportion to the force and in inverse to the mass of the body.

Newton's second law of motion in a mathematical equation: F = ma

A ______is a set of items or interactions considered a distinct physical entity for the purpose of study.

A ______is a reasonable explanation for observed phenomena in terms of a simple model that has familiar properties. A useful theory, in addition to explaining past observations, serves to predict behavior that has not yet been observed.

A ______is a replica or description designed to show the structure or workings of an object, system or concept. A model can help build hypotheses.

ex. Atomic theory is a theory that involves an ______model that helps scientists picture the way an observed phenomenon could be produced.

Hypotheses must be tested in controlled experiments. A controlled experiment is an experiment involving manipulation of a ______variable or factor.

Scientific Notation Review Section 1-2

A number is expressed in scientific notation when it is in the form a x 10n . Where ____ is between 1 and 10 and ______ is an integer. When the original number is less than 1, the exponent is ______. When the original number is more than 1, the exponent is ______.

Practice. Convert to proper scientific notation.

25,000 = ______123,100 = ______12 = ______

2 = ______273 x 103 = ______0.268 = ______

0.00034 = ______0.000000009732 = ______

Practice. Convert from scientific notation.

2.7 x 104 = ______35.7 x 103 = ______

2.7 x 10-4 = ______35.7 x 10-3 = ______

Practice Section Review p. 9 Q 1-5

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In the study of physics it is important to recognize the fact that unless a property can be ______and compared with some kind of standard, it is of limited use to the scientist. Without ______ there can be no science.

Basic Units of the Systeme International (SI)

Dimension Unit

lengthmeter, m

masskilogram, kg

timesecond, s

There are seven basic units in the SI system. These seven can be combined to form ______units using multiplication and division.

ex. The unit for speed is m/s which is a meter divided by a second.

ex. The Newton, N, is the unit for ______. The Newton is equivalent to kg m / s2 which is a kilogram multiplied by a meter and all divided by a second times a second.

Prefixes are used for extremely high and extremely ______numbers. Page 12

Are units important? (Answer this question as you watch the video clip)

______

______

To convert measurements, use a conversion factor that is a ______. The numerator or top number should include the prefix you want to convert to. The denominator or bottom number should include the unit you want to convert from. Use Table 1-3 on page 12.

ex. Convert 5000 cm to m. 1 cm = 10-2 m or 1 cm = 1 x 10-2 m or 1 cm = 0.01 m

5000 cm = 5000 cm x 0.01 m = 5000 x .01 = 50 m

11 cm1 x 1

ex. Convert 25,000,000,000 m (micro meters) to a Gm (giga meter).

A less mathematically complex way to convert prefixes is to count the places or steps for the decimal to move by using the exponents. For example, 1 m = 10-6 m and 1 Gm = 109 m, so converting a m to a Gm is –6 - 9 = –15 places the decimal needs to move or 15 places ______.

(from ______to)

For meter, liter, gram, or seconds, use 100.

Convert these:

0.00985 kg = ______ng

2 nm = ______Mm

3.4 x 106 Tm = ______Pm

0.0045 ml = ______kl

55.6 km = ______mm

2389 s = ______s

217 m = ______km

ex. Writing your answer using prefixes, how many seconds are in (show your work):

a. a 7 day week

b. 17 (365 day) years

Using a conversion factor is often the easiest method, especially with mixed units.

1 hour = 60 minutes1 minute = 60 seconds1 hour = ______seconds

ex. Convert 15 km/hr to m/s 1 km = 103 m or 1 km = 1 x 103 m or 1 km = ______m

15 km / hr is equivalent to15 km

1 hr

15 km x1000 m x1 hr =______= ______m/s

1 hr1 km3600 s

ex. Convert 55 km/hr to m/s(Show your work.)

ex. Convert 9 m/s to km/min(Show your work.)

x. Convert 24 m/s to km/hr(Show your work.)

ex. Convert 88 km/hr to m/s(Show your work.)

Practice p. 15 Q 1-5

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Accuracy vs. Precision & Notes Section 1-3

Certainty in science: The ______of a scientific conclusion is always limited by the method of observation and, to a certain extent, by the person who made it.

______is the extent to which a reported measurement approaches the true value of the quantity measured.

A lack of accuracy can be caused by ______error. Repeating measurement can reduce human error. Two other errors that effect accuracy are ______error and instrument error.

______describes how exact a measurement can be. It is also the agreement among the measurements – how close they are to each other.

1.325 m is more precise than 1.3 m. If you measured the length of a box and your measurements are 11.2 cm, 11.3, cm, and 11.4 cm, then you are precise in your measuring, regardless of the actual length of box.

A lack of ______is usually due to limitations of the measuring instrument and is not the result of human error or lack of calibration.

______are those ______in a number that are known with certainty plus the first digit that is uncertain.

Using the rules on page 17, how many significant digits are there in the following?

156 - _____9,000,000 - _____1760 - _____381,000 - _____

4000. -_____905 - _____ 0.00236 - _____ 0.020750 - _____

9.73 x 104 -_____8.520 x 102 - _____70.040 - _____156.18 - _____

Using the rules on page 18 and 19, how many significant digits are there in the following?

16 x 100 = 1600 = 2000 ______251 x 0.34 = 85.34 = 85 _____

Practice: P. 20 Section Review Q 1-4

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Physicists use mathematics to analyze and summarize their observations of an event. They then use the mathematical relationships among physical quantities to help ______what will happen in new situations.

To simplify expressions, physicists and mathematicians use letters, such as t for time, y for vertical distance, or  for difference or .

y = 4.9 t2 should be read as 'the change in y equals 4.9 times the change in t2.

Physicists make their work easier by summarizing data in and and by abbreviating quantities in equations.

One of the purposes for this is to discover that may exist among the quantities measured.

Tables, graphs, and equations can make ______easier to understand.

In a proportion, the ratio of two quantities, written as a fraction, is a constant and always results in the graph of a straight line.

The graph of two quantities does NOT always result in a straight line. The shape could be a hyperbola, a parabola, or any other non-straight curve.

The estimation of values between the plotted points on a graph is ______.

The estimation of values beyond the plotted points on a graph is ______.

The ______of a line in physics often describes a quantity. For example, on a time vs. distance graph, the slope of the line is the speed of the object. m = (y2 – y1) / (x2 – x1)

A graph must contain:

1. a ______
2. axes that are labeled with quantity they represent and the ______
3. evenly spaced ______on the axes
4. a ______if more than one curve is on the graph.

The independent variable is usually placed on the horizontal axis, and the dependent variable is usually placed on the vertical axis. The dependent variable changes because the independent variable changes. Time is almost always an ______variable.

A table should always include a ______indicating which table it is, such as Table 2, and what the data refers to and where the data was collected, such as Mass-Weight Experiment. Each column and/or row should be clearly labeled.

Table 1 - Time vs Distance Experiment

ex. Create a graph from the following data that compares the weight and mass of high school students, and from your graph, answer questions 1 - 3.

Table 2 - Mass/Weight Experiment

1. From your graph, interpolate the mass of a student who weighs 630 N. ______

Interpolate means estimation of values between the plotted points. Extrapolate means estimation of values outside the plotted point range.

1. From your graph, extrapolate the weight of a student with a mass of 110 kg. ______
2. Does the graph show a direct proportion between mass and weight? Explain ______
3. Find the slope of the line. Show your number substitution. m = (y2 – y1) / (x2 – x1)

m = (______) / (______)

m = ______

Order of magnitude

The Order-of-magnitude is a numerical approximation of the magnitude or ______of a quantity to the nearest power of ten.

0.000110-410101

0.00110-3 100102

0.0110-2 1000103

0.110-1 10,000104

1100

For the exponent on the 10: If a number is in proper scientific notation and the single digit to the ______of the decimal point is 5 or greater (5, 6, 7, 8, 9) ______1 to the exponent. If it is less than 5 (1, 2, 3, 4), leave the exponent as is.

7.25 x 102 (725) is closer to 1000 than it is to 100, so the order of magnitude would be ______(which is 1000 written as a power of 10).

7.25 x 10-2 (0.0725) is closer to 0.1 than it is to 0.01, so the order of magnitude would be ______(which is 0.1 written as a power of 10).

ex. Give the order of magnitude of the following:

3.75 x 10 4 ______8.608 x 10 –8 ______

6.02 x 10 23 ______4.99 x 10 –13 ______

the height of a human ______

the length of a roach/water bug ______

Extra Practice

7000 ______2 ______5496 ______

.0034______.0075 ______6491 ______.00425 ______

Order-of-magnitude calculations provide a quick way to ______the appropriateness of an answer.

ex. You are driving 725 km across the country to visit a friend. Your average speed is 88 km/hr. How long will it take you to get there? Use order-of-magnitude for your calculation. BALANCES – triple beam balance, spring balance, inertial balance

A triple beam balance is used to measure the ______of an object, usually in kilograms, and a spring balance is used to measure the ______of an object in the unit of Newton.

An inertial balance is used to compare masses by measuring the period of vibration when a mass is placed on the pan of the balance and the pan is set in horizontal motion. The time for a single vibration of an inertial balance is called the ______of the balance.

With an inertial balance, it is often more convenient to measure the periods of several known masses and then plot a ______of the resulting data. The value of the unknown mass can then be read directly from the graph after the period is measured.

Inertial balances are used to determine the ______of an object while in space. Mass doesn’t change but the weight does since weight depends on “g” or the acceleration due to ______of the planet that you are on.

Abbreviations for variables and units

v = ______∆= ______Σ = ______

∆y = ______∆t = ______m= ______

m=______s=______

Independent Practice: p. 25 Q 2-5

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