Lecture notes for Physics 10154: General Physics I

1 Lecture notes for Physics 10154: General Physics IHana DobrovolnyDepartment of Physics & Astronomy, Texas Christian University, Fort Worth, TXDecember 3, 2012 Contents1 The tools of Physics .. method .. conversion .. analysis .. figures .. systems .. Problem solving ..112 Motion in one Displacement .. Velocity .. interpretation of velocity .. velocity .. Acceleration .. acceleration .. 1-D motion with constant acceleration ..183 Vectors and Two-Dimensional Vector properties .. , velocity and acceleration in two dimensions .. Motion in two dimensions.

2 274 Laws of Newton s first law .. Newton s second law .. Newton s third law .. Friction ..325 Work and Work .. Kinetic energy .. and nonconservative forces .. Gravitational potential energy .. Spring potential energy ..4416 Momentum and Momentum and impulse .. Conservation of momentum .. in two dimensions ..517 Rotational Angular displacement, speed and acceleration .. angular acceleration .. between angular and linear quantities .. Centripetal acceleration .. Gravitation .. s Laws .. Torque .. of gravity.

3 Torque and angular acceleration .. of inertia .. Rotational kinetic energy .. Angular momentum ..728 Vibrations and Return of springs .. of simple harmonic motion .. simple harmonic motion and circular motion .. Position, velocity and acceleration .. Motion of a pendulum .. Damped oscillations .. Waves .. of waves .. of a wave .. of waves .. of waves .. Sound waves .. and intensity of sound waves .. doppler effect .. Standing waves .. Beats ..869 Solids and States of matter .. matter .. Deformation of solids.

4 S modulus .. modulus .. modulus .. Pressure and fluids .. Buoyant forces .. submerged object .. submerged object .. Fluids in motion .. of continuity .. Bernoulli s equation ..9510 Thermal Temperature .. Thermal expansion .. Ideal gas law ..993 List of Converting between Cartesian and polar coordinates.. The projections of a vector on thex- andy-axes.. Graphical addition of vectors..254 Chapter 1 IntroductionPhysics is a quantitative science that uses experimentation and measurement to advance our understandingof the world around us. Many people are afraid of Physics because it relies heavily on mathematics, but don tlet this deter you.

5 Most Physics concepts are expressed equally well in plain English and in equations. Infact, mathematics is simply an alternative short-hand language that allows us to easily describe and predictthe behaviour of the natural world. Much of this course involves learning how to translate from English toequations and back again and to use those equations to develop new The tools of physicsBefore we begin learning Physics , we need to familiarize ourselves with the tools and conventions used Scientific methodAll sciences depend on the scientific method to advance knowledge in their fields.

6 The scientific methodbegins with a hypothesis that attempts to explain some observed phenomenon. This hypothesis must befalsifiable, that is, there must exist some experiment which can disprove the hypothesis. The next step in theprocess is to design and perform an experiment to test the hypothesis. If the hypothesis does not correctlypredict the results of the experiment, it is thrown out and a new hypothesis must be developed. If it correctlypredicts the result of that particular experiment, the hypothesis is used again to make new predictions thatcan be experimentally tested. Although we will often speak of physical laws in this course, they are reallyall hypotheses that have been extensively compared to experiments and consistently correctly predict theresult, but as our body of knowledge expands there is still the possibility that they may not be completelycorrect and so they will forever remain MeasurementOne of the fundamental building blocks of Physics is measurement.

7 Essentially, measurement assigns anumerical value to some aspect of an object. For example, if we want to compare the height of two people,we can have them stand side by side and we can easily see who is taller. What if those two people don thappen to be in the same place, but I still want to compare their heights? I can use some object, comparethe height of the first person to that object, then compare the height of the second person to that object this is measurement. This will only work, of course, if I use the same object to measure both people, , Ineed to standardize the measurement in some way.

8 I can do this by defining a , the entire world has agreed on a standard system of measurement called the SI (syst`eme interna-tional). Here are some of the fundamental units of the SI that you will encounter in this course:5 Table : Prefixes used for powers of ten in the metric systemPower Prefix Abbreviation10 18attoa10 15femtof10 12picop10 9nanon10 6micro 10 3millim10 2centic10 1decid101dekada103kilok106megaM109gigaG1 012teraT1015petaP1018exaEFundamental unit for lengthis called themeterand is defined as the distance traveled by light in avacuum during a time interval of 1/299 792 458 unit of massis called thekilogramand is defined as the mass of a specific platinum-iridiumalloy cylinder kept at the International Bureau of Weights and Measures in unit of timeis called thesecondand is defined as

9 9 192 631 700 times the period ofoscillation of radiation from the cesium metric system builds on these fundamental units by attaching prefixes to the unit to denote powersof ten. Some of the prefixes and their abbreviations are shown in Table According to this table then1000 m (m is the abbreviation for meter) = 1 km = 100 dam = 100000 notationSince it is cumbersome to read and write numbers with lots of digits, scientists use a shorthandnotation for writing very small or very large numbers. Instead of writing 100000 cm as in theexample above, I could write 105cm where the 105tells me to multiply by 100 000 (ormove the decimal 5 places to the right).

10 You might also sometimes see this written as cm,which is the computer shorthand for remember to write down the units for any quantity. Without the units, we have noway to understand how you made the measurement! Unit conversionThe fundamental units of the meter and kilogram are not the familiar units of feet or pounds that aretypically used in the United States. You may occasionally be asked to convert from the imperial system(foot, pound) to the SI system (meters, kilograms). The method for unit conversion introduced here isalso useful for converting between different units within a particular measurement system ( meters tokilometers).