MOTION (PHYSICS UNIT):

Chapters 9-12

Converting to Scientific Notation:

Rule 1: Move the decimal to where there is one nonzero digit to the left of the decimal point.

(This creates a number between 1 and 10)

Rule 2: If the decimal point is moved to the left, the exponent is positive.

Rule 3: If the decimal point is moved to the right, the exponent is negative.

Scientific notation Standard form:

Move the decimal to either the left (if the exponent is negative), or to the right (if it is positive), the number of spaces indicated by the exponent.

Ex: 2.38 x 10^-5 becomes….

0.0000238

Significant figures:

(1) All nonzero digits are significant: 1.234 g has 4 sig. figs.

(2) Zeroes between nonzero digits are significant: 1002 kg has 4 significant figures

(3) Leading zeros to the left of the first nonzero digits are

not significant; they merely indicate place value: 0.001 oC has only 1 significant figure

(4) Trailing zeroes that are also to the right of a decimal are significant:

0.0230 mL has 3 significant figures,

Metric Conversions:

1km = 1000m, 1m = 100cm, 1cm =10mm

*The meter is the base unit for distance in physics, that means physicists (and physics students) convert distances to meters when doing calculations:

“kilo” means “thousand” “centi” means “hundred” “milli” means “thousandth”

Converting units of time:

60 seconds = 1 minute, 60 minutes = 1 hour, try these:

15 mins = _______ hours 300 secs = ______min

2.0 hours = _______ min 0.5 hours = ______min

38 min = _______ sec 42 min = ________hrs

3.5 hours = ______ sec 160 sec = _______ min

1.24 hours = _____ min 90 min = _______ sec

Calculating speed:

Speed = Distance Time

Average speed = Total distance, divided by total time.

Express your answers in the proper units, such as: Kilometers per hour (km/h), miles per hour (mph), meters

perhour (m/h), meters per second (m/s), centimeters per

second (cm/s), feet per second (f.p.s.) etc

*m/s is the base unit for speed/velocity in physics.

Distance-Time Graphs:

*Speed can be represented by the letter “v” for velocity, which is the same as speed when you are travelling in a straight line (assumed in these questions).

The ‘s in the equation represent “change in”.

Speed can be determined from the slope of a line of best fit from a distance-time graph.

See examples on pages 364 and 365. # 5 (a-f) on page 365 Now try # 11 and 12 (a and b only) on pages

376-377.

Speed vs velocity:

Distance = how far an object travels. Displacement = how far away an

object is from where it started.

*If you run one lap around a circular ¼ mile track, your distance traveled is 1/4 mile, your displacement would be 0.

Speed vs velocity:

Speed is a measurement of magnitude (distance) only; it does not take into account direction.

It is called a scalar quantity.

Velocity is a measurement of both magnitude and direction (displacement).

It is therefore called a vector quantity.