Friday 3 Sep:

Key Idea: Pre-Test Newton's Laws

Mult & Div (estimate) with exponents

 Journal #2: 

• What is the difference between precision and accuracy?

Precision means that it is repeatable (done many time with same results)

Accuracy means close to accepted value.

Did you turn in Parent Forms & Pay Course Fee

Questions from H/W assignment:

L#1:  1-4, 7-12, 15-20    Due Tuesday 7 Sep

  L#2:  1-5, 7-10, 15-17   Due Wed 8 Sep

  L#3:  1-12, 14 - 17, 19   Due Friday 10 Sep

Notes :

1. Estimation (no calculator): Use one sig fig and answer is one sig fig

(1.5 x 10⁴)(8.39 x 10¹³)   =  2 x 10¹⁸

2. Conversion:

• Work Coefficient
• Work Exponents
  • (multiply = add exponents)
  • (divide    =  subtract exponents)
• Cross out Labels

8  x 10⁹  cm/sec   = ____ km/hr

    (4.20 x 10² km/hr) (100,000 cm) (1.00 hr)               

                                                (1.00 km)    (3600sec)

            à 11,666.6 or 11,700 cm/sec 

Notes:

a.    What is a ratio?

b.   What does proportional relationships mean?

 Direct:  y goes up, x goes up  (y = k x)

 Inverse: y goes up, x goes down  (y = k/x)  or   y = k (1/x²)

Examples

·             If an object travels at a constant speed, then the distance traveled is proportional to the time spent traveling.

·             The circumference of a circle is proportional to its diameter, with the constant of proportionality equal to π.

·             The amount of force acting on a certain object from the gravity of the Earth is proportional to the object's mass.