PHYSICS MATH REVIEW

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PHYSICS MATH REVIEW
MATHMATICAL!

• Aw yeah math.

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Know your symbols!

• v, a, t, d, etc. VARIABLES
• in algebra they can stand for anything
• in PHYSICS they only stand for a specific
  type of quantity!
• v velocity, a acceleration, t time, d
  distance, F force, and so on

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Know your symbols!

• Variables have superscripts and subscripts
• i.e vi2
• The subscripts will stand for a term (i means
  initial, f means final). Or they are used
  to keep track of which value youre referencing.
  (i.e. v1 means velocity of 1st object)

superscript (super higher ?) Will denote an
exponent.
subscript (sub below ?) Used to modify the
variable.
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Know your symbols!

• ? DELTA
• - You might recognize this from chemistry!
• - Its the greek symbol for the letter D
• In front of a variable it means change in
• i.e. ?t change in time
• To find ?, just subtract the initial from the
  final.
• i.e. ?v vf vi (change in velocity v final
  v initial)

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Know your UNITS

• Every variable in physics will have units
  attached to it.
• For calculations, the units should always be the
  same
• i.e. You cant subtract 60 seconds from 3 hours
  directly. You have to give them the same units!

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Know your UNITS

• Some common units in physics
• C Celsius (used for temperature)
• m meters (standard unit of length)
• s seconds (standard unit of time)
• kg kilogram (standard unit of mass)
• N Newton (standard unit of force)
• J Joule (standard unit of energy)

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Know your UNITS

• Physics uses the metric system (meters, Celsius,
  grams) but you should be aware of common English
  units as well (feet, miles, pounds).
• Try to have an idea of what reasonable units are
  for a given situation. (You wouldnt measure a
  table in miles.)

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Scientific Notation

• Used to denote numbers with excess
  leading/trailing zeros.
• .00035 3.5 x 10-4
• 7,630,000 7.63 x 106
• Always have only 1 digit before the decimal.
• Adjust the decimal place to the right or left
  accordingly.

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Solving for Variables

• Order of operations!
• PEDMAS (),2,/,, , -
• Remember that if two variables are added or
  subtracted over a denominator, they are treated
  as if they are in parenthesis.
• i.e. (a (vf-vi)/?t )

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Solving for Variables

• Know the inverse of each operation
• - ( vs -), ( vs / ), (2 vs v )
• Isolate the desired variable through reverse
  order of operations

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Solving for Variables

• Examples
• 3b26 18
• 3b2 18 6 12
• b2 12/3 4
• b v(4) 2
• b 2
• Remember that if parentheses are involved, you
  must deal with everything outside of the
  parenthesis first. (inverse order of operations)

(36 vi) / 12 7 (36 vi) 7 12 84 vi
72 36 48 vi -48
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Solving for Variables

• Sometimes youll have to isolate a variable, even
  though there are other variables in the equation.
  Just treat them the same as other numbers, and
  follow the same procedure.
• Ex Fma (solve for a), a F/m
• Ex volume lhw (solve for w), w v/(lh)

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Calculating Variables

• First, find the equation dealing with your
  variable
• Next, substitute the given variables with their
  numbers
• Make sure all units are the same
• Solve the single variable equation!

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Calculating Variables

• Ex An arrow flies by with a speed of 3.6 m/s.
  How long does it take to travel 40 cm?
• Step 1 Looking for time and we know distance
  and speed.
• v d/t
• Step 2 Plug in the values
• (3.6 m/s) (40cm) / t
• Step 3 Make the units match
• 40 cm .4 meters
• Step 4 Solve the equation
• 3.6 .4/t
• 1/t (3.6)/.4 9
• t .11 seconds

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Things to Remember

• In physics, answers should be given in decimal
  form (no fractions).
• Decimals should be kept to correct amount of
  significant figures

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MATH PRACTICEComplete these problems in your
notebook. Work on your own or in small groups.
Solve for the variable

• Write the following in Scientific Notation
• 0.07882
• 118000
• 0.00002786
• 4. 382,000,000

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Metric Conversion

• kilo- (k-) thousand 1000 x base
• hecto- (h-) hundred 100 x base
• deka- (da-) ten 10 x base
• Base (meters, grams, liters)
• deci- (d-) tenth .1 x base
• centi- (c-) hundredth .01 x base
• milli- (m-) thousandth .001 x base
• micro- (µ-) millionth 1 x 10-6 x base
• nano- (n-) billionth 1 x 10-9 x base

3600 seconds 1 hour
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Conversion review

• Convert 360 km/hr to m/s

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Challenge Question

• A bear is charging with a velocity of 36 km/hr.
  If it maintains that velocity for 30 seconds, how
  many meters does it travel?

Tips 1) Find the right equation on your STAAR
chart. Write it down. (Hint It will have time
and distance as variables) 2) Plug in the
appropriate values 3) Make sure the units are
the same (km/hr to m/s) 4) Once all of the above
is done, then try and solve the equation.
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Answer

• A bear is charging with a velocity of 36 km/hr.
  If it maintains that velocity for 30 seconds, how
  many meters can it travel?
• Formula vd/t
• Values 36 km/hr d / 30s
• Units ?

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Conversion review

• Convert 36 km/hr to m/s

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Answer

• A bear is charging with a velocity of 36 km/hr.
  If it maintains that velocity for 30 seconds, how
  many meters can it travel?
• Formula vd/t
• Values 36 km/hr d / 30s
• Units 36 km/hr 10 m/s
• Solve for d d (10m/s)(30s)
• 300 meters

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Question 1

• A linebacker has a mass of 150 kg. If he hits the
  receiver with a force of 675 kgm/s2 (Newtons).
  What was his acceleration?

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Answer 1

• A linebacker has a mass of 150 kg. If he hits the
  receiver with a force of 675 kgm/s2 (Newtons).
  What was his acceleration?
• Formula F ma
• Values 675 N 150kg a
• Units already match (kg kg)
• Solve for a a 675N/150 kg 4.5 m/s2