8thGradePhysics

Yukta:

This last week, we looked at units 5.01 and 5.02. So, review the units and answer the two questions at the end of unit 5.01. 

For unit 5.02, after the introduction, we had a nice time changing from one unit of measurement to the other. We also saw how mercury moved up and down as temperature of water rose and fell. Therefore, this is the assignment:
            (i) Find out the formula for changing celcius to farenheit and vice-versa.
            (ii) Use the formula to change 212, 100, 300, 36 in degrees celcius to degrees farenheit
            (iii) Us ethe formula to change 78 and 92 degrees farenheit to degrees celcius.
Type the answers in word format and sent to my box or hand write them, scan and send. Whichever option you prefer is fine with me.

We miss you in class! See you soon.


Election Holiday Assignment

Review unit 4.04: page 84 - 85 and answer questions 1-6, unit 4.05: page 86-87, then questions 1-3 and finally unit 4.06: page 88-89 and questions 1-2. I do hope you have your textbook with you.

See you when you return to school.


Week Two:
Hello and welcome to week two of virtual learning.  Please recall that
                density = mass/volume 
My goal this week is to see you combine units correctly as you review how to calculate density. So, apply this formula to questions 8-11 on page 22.

 Remember to combine the units  correctly.

 Week One:
Our focus this week is to
   - combine units correctly
   - write the appropriate SI unit for physical quantities
   - write numbers in scientific notation
   - use the micrometer screw gauge (suspended until we meet in school)

 In combining units, the appropriate unit must be written in the numerator and the denominator of the equation for the resulting equation on the right hand side to be valid. Check page 10 of your textbook. I also have a hand-written example below.

8th Grade Virtual

SI base units
The SI is founded on seven SI base units for seven base quantities assumed to be mutually independent, as given below

SI base units

SI base unit Base quantity Name Symbol length meter m mass kilogram       kg time second s electric current ampere A thermodynamic temperature       kelvin K amount of substance mole mol luminous intensity candela cd

 
SI derived units
Other quantities, called derived quantities, are defined in terms of the seven base quantities via a system of quantity equations. The SI derived units for these derived quantities are obtained from these equations and the seven SI base units. Examples of such SI derived units are given in Table 2, where it should be noted that the symbol 1 for quantities of dimension 1 such as mass fraction is generally omitted.

Table 2.  Examples of SI derived units
	SI derived unit
Derived quantity	Name	Symbol
area	square meter	m2
volume	cubic meter	m3
speed, velocity	meter per second	m/s
acceleration	meter per second squared	m/s2
wave number	reciprocal meter	m-1
mass density	kilogram per cubic meter	kg/m3
specific volume	cubic meter per kilogram	m3/kg
current density	ampere per square meter	A/m2
magnetic field strength	ampere per meter	A/m
amount-of-substance concentration	mole per cubic meter	mol/m3
luminance	candela per square meter	cd/m2
mass fraction	kilogram per kilogram, which may be represented by the number 1	kg/kg = 1

 

The table on page 11 in your textbook shows how to scale units up or down.

Watch the video below for more information on the SI units.

Scientific Notation

(source: http://www.mathsisfun.com/numbers/scientific-notation.html)

Scientific Notation (also called Standard Form in Britain) is a special way of writing numbers:

Like this:
Or this:

It makes it easy to use big and small values.

The number is written in two parts:

• Just the digits (with the decimal point placed after the first digit), followed by
• × 10 to a power that puts the decimal point where it should be
  (i.e. it shows how many places to move the decimal point).

In this example, 5326.6 is written as 5.3266 × 10³,
because 5326.6 = 5.3266 × 1000 = 5.3266 × 10³

Assignment:
Answer the following questions in your notebook for submission next Tuesday.
1. Explain how units should be written correctly in physics
2. (i) Why is the SI unit important? (ii) What is the main difference between fundamental and derived units?

3. Write the following in km (i) 2000m (ii) 200m (iii) 2 x10⁴m

4. Using the scientific notation, write the following to two significant figures:

        (i) 1500m  (ii) 1500000m  (iii) 0.15m  (iv) 0.015m

5. What is the SI unit of the following quantities - length, mass and time?

6. Go to page 22 and answer #1,4 and 7.

We will begin next week's work with measuring with greater accuracy. By the time you get to school for traditional schooling, we will have practical demo. I miss you all.

The video below explains how to use the micrometer screw gauge.