01_physics_lecture_16 Feb 2013

MS101: PhysicsMS101: PhysicsDr. Ahmed Amin HusseinDr. Ahmed Amin Hussein

ahussein32125@gmail.com20132013

May 3, 2023 Prepared By: Dr. Ahmed Amin 1

Agenda for TodayAgenda for Today

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ExamsExams

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Midterms and Final Exam:

•Questions on tests will look like those we do in the class and in homeworks•No surprises

Final Grade

•Mid Term Assessment (MTA) ------- 30%•Tutor Marked Assignment (TMA) ---- 20%•Final Examination ----------------------- 50%

Why Study Physics?Why Study Physics?

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Physics is the foundation of every science (astronomy, biology, chemistry…).

Many pieces of technology and/or medical equipment and procedures are developed with the help of physicists.

Studying physics will help you develop good thinking skills, problem solving skills, and give you the background needed to differentiate

between science and pseudoscience.

Standard QuantitiesStandard Quantities

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UnitsUnits

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Length:Length:

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Time:Time:

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Mass:Mass:

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Some Prefixes for Power Some Prefixes for Power of Tenof Ten

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Scientific notationScientific notation

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Scientific notationScientific notation is based on powers is based on powers of the of the base number 10base number 10. The scientific . The scientific notation in standard form is written as:notation in standard form is written as:

   A x 10A x 10nn

wherewhere(a)(a) 1 1 A < 10 and A can be an integer or A < 10 and A can be an integer or decimal number.decimal number.

(b)(b) nn is a positive integer for a number is a positive integer for a number greater than one or a negative integer for a greater than one or a negative integer for a number less than one.number less than one.

Proportions:Proportions:

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BA

BA 1

A is proportional to B. The value of A is directly dependent on the value of B.

A is proportional to 1/B. The value of A is inversely dependent on the value of B.

Example (1):Example (1):

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weightcost

The more you buy, the more you pay. This is just the relationship between cost and weight.

To change from to = we need to know the proportionality constant.

(weight)pound)per (cost cost

For items at the grocery store:

Example (2):Example (2):

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The area of a circle is .2rA

The area is proportional to the radius squared. 2rA

The proportionality constant is .

Example (3):Example (3):

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Example: If you have one circle with a radius of 5.0 cm and a second circle with a radius of 3.0 cm, by what factor is the area of the first circle larger than

the area of the second circle?

8.2cm 3cm 5

2

2

22

21

2

1 rr

AA

The area of a circle is proportional to r2:

The area of the first circle is 2.8 times larger than the second circle.

Density:Density:

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Dimensional AnalysisDimensional Analysis

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Example (1):Example (1):

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Example (2):Example (2):

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Converting between different systems of unitsConverting between different systems of units

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Example (3):Example (3):

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Significant FiguresSignificant Figures

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Significant FiguresSignificant Figures

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Derived UnitDerived Unit

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The SI unit of energy is the joule.

1 joule = 1 kg m2/sec2

Derived unit Base units

A derived unit is composed of combinations of base units.

TMA ExercisesTMA Exercises

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Problems :

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