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…. 

Significant figures: (1) All nonzero digits are significant: 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: o C has only 1 significant figure (4) Trailing zeroes that are also to the right of a decimal are significant: 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 per hour (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

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.