Energy Flow in Technological Systems

December 01, 2014

Energy Flow in Technological Systems

December 01, 2014

Scientific Notation (Exponents)

Scientific notation is used when we are dealing with very large or very small numbers. A number placed in scientific notation is made up of two parts

a) The first part is a number between 1.00 and 10.0

b) The second part is x 10w where w is the number places the decimal point was moved in order to write the number in scientific notation; to the right is negative (small number), positive is to the left (large number)

Ex: 3456 can be written as

0.0987 can be written as

December 01, 2014

Significant DigitsRule to determine the amount of significant digits in a number

Find the first nonzero number. All numbers to the right of that number including that number, including zeros, are also significant.

WHEN MULTIPLYING OR DIVIDING ALWAYS ROUND TO THE FEWEST SIGNIFICANT DIGITS FOUND IN THE CALCULATION!

December 01, 2014

ConversionsA conversion is an expression of a number in a different unit. We are very aware that 1 dozen objects represents 12 objects, or 1.000 km equals 1000 meters. We will be using the method of multiplication in order to obtain the equivalences. We will always be multiplying by the equivalent of the number one (1).

Ex 1: Convert 2.500 km to m.

Ex 2: Convert 3.00 hours to minutes.

December 01, 2014

Ex 3: Convert 7654 sec to minutes.

Ex 4: Convert 200 km/h to m/s.

December 01, 2014

Ex 5 Convert 13.8 m/s to km/h.

December 01, 2014

A simpler and faster method of converting

- m/s to km/h is mutliply by 3.6

- km/h to m/s is divide by 3.6

December 01, 2014

MotionThe changing position of an object relative to a reference point.

Uniform MotionAn object is moving a constant rate.

December 01, 2014

Average SpeedUniform motion that involves traveling a distance in a specified time.

V = dt

average speed = distance travelledtime elapsed

Rearranging it:

December 01, 2014

Steps for solving problems.

1. Write down your variables.

2. Write down the appropriate formula (rearrange if necessary).

3. Substitute the numbers (including units) into the formula.

4. Make sure that the answer has appropriate units and number significant digits.

December 01, 2014

A person walks 10.0m away from a stop sign in 5.00s. What is the average speed of the person?

December 01, 2014

GraphsImportant information to consider when drawing (plotting) a graph.

1. Labels (Title, x axis and y axis including units for both).

2. Equal increments along the x and y sides. The increments along the x axis need not be the same as those along the y axis.

3. If it is a linear relationship, a line of best fit must be drawn.

December 01, 2014

Graph this data

December 01, 2014

Distance vs Time Graph

The slope tells us the speed. The steeper the slope the faster the average speed.

If a line is flat, it means that the person is traveling at a constant rate.

December 01, 2014

A

BC

D

E

Describe the motion between:A to B

B to C

C to D

D to E

December 01, 2014

SlopeThe steepness (slope) of a distance-time graph represents the average speed of each person.

Definition of Slope: It represents the steepness of the line. The steeper the line, the greater is its slope. A graph is always read from left to right as you would a book.

Slope = RiseRun

or y2 - y1

x2-x1

December 01, 2014

Calculate the slope of the following:

A

B C

D E

F

A to B

B to C

C to DD to EE to F

December 01, 2014

Speed vs Time Graph

December 01, 2014

If slope is positive the speed is increasing

If slope is negative the speed is decreasing

If slope is 0 the speed is constant/uniform.

Speed vs Time graph

The area under the graph is the distance travelled.

December 01, 2014

Describe the speed between each point.

December 01, 2014

How much further did the person travel between points D and E compared to A and B?

December 01, 2014

Page # 128 #1,2,3

Page # 120 # 4

Page 133 #5

Page 135 #1,2,4,5,6