My Motivational Speech Focus on learning, not on grades. Learning brings success, and life-long...

My Motivational Speech

• Focus on learning, not on grades. Learning brings success, and life-long learning brings life-long success.

• If I offered to hire you for one month (30 days straight!) and offered to pay you $1,000,000 or 1 penny on the first day, but double your wages each day, which would you accept?

• If you take the penny, you make over 5 million dollars on the 30th day (over 10 million for the month)

• It’s how you grow that’s important, not how much you start with!

Chapter 01

Measurements

Units

• For us to communicate “how much” something is, we must use units.

• What if I were to offer a job to you that pays an annual salary of 60,000 per year? Would you accept the job?

• Three of the fundamental units used in the SI system (SI is the most common system of units used in science)– unit of mass, kilogram (kg)– unit of distance, meter (m)– unit of time, second (s)

Unit Prefixes

prefix meaning power of 10

micro one-millionth 10-6 1/1,000,000

milli one-thousandth 10-3 1/1000

centi one-hundredth 10-2 1/100

kilo one thousand 103 1000

mega one million 106 1,000,000

giga one billion 109 1,000,000,000

tera one trillion 1012 1,000,000,000,000

Scientific Notation

There is an easier way to express numbers so that we don’t have to count all those digits and commas.

9850 kg = 9.85 x 103 kg = 9.85 x 106 g

299,792, 458 m/s = 2.99792458 x 108 m/s

384,403 km = 3.84403 x 105 km = 3.84403 x 108 m

The mass of the earth is 5.97 x 1024 kg. Do you really want to write that number without using scientific notation?

Poll

The width of a DNA molecule is about 0.0000000002 m. In scientific notation, this is

1.2 x 10-8 m

2.2 x 108 m

3.2 x 10-10 m

4.2 x 1010 m

5.None of the above.

Chapter 1Measurement

Matter & InteractionsPHY 221 – Dr. Aaron Titus

Poll

Earth’s equatorial radius is 6378 km. What is this number written in scientific notation?

1.6.378 x 101 m

2.6.378 x 10-3 m

3.6.378 x 102 m

4.6.378 x 103 m

5.None of the above



Unit Conversion

• Write your conversion factor as a ratio equal to 1.

• Multiply the quantity by 1 (the conversion factor) so that units cancel as needed.

• Multiply by 1 as many times as needed.

Poll

A football field is 100 yd long. What is its length in meters?

1.100 m

2.109 m

3.9 m

4.82 m

5.91 m



Poll

My office has a volume of 1000 ft3. What is its volume in m3?

1.394 ft3

2.305 m3

3.0.3 m3

4.28 m3

5.None of the above.



Poll

Suppose that you burn 280 calories of energy while working out for 20 minutes on an elliptical machine in the gym. How many joules of energy did you burn?

1. 1170 J

2. 67 J

3. 280 J

4. 5600 J

5. None of the above



Poll

By measuring a person’s density, one can calculate his % body fat. If a person has a density of 1.05 g/cm3, what is his density in kg/m3?

1. 1.05 x 103 kg/m3

2. 1.05 x 106 kg/m3

3. 1.05 x 102 kg/m3

4. 1.05 x 104 kg/m3

5. 1.05 x 109 kg/m3



Proportionality

• Sometimes we want to know how one variable depends on another variable.

• For example, for a circle

so doubling the radius increases the circumference by a factor of 2.

• When one variable is directly proportional to another variable, we write

Poll

The volume of a cylinder is V = πR2h. If you double the radius of the cylinder, how much more volume will it have?

1. It’ll have the same volume.

2.2 times more volume.

3.4 times more volume

4.8 times more volume

5.Half as much volume.



My Motivational Speech Focus on learning, not on grades. Learning brings success, and life-long...

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