OAR EXAM
what is the total number of degrees in the three angles of a triangle?
180
Newtons Laws
1st- object in motion will stay in motion, object at rest will stay at rest 2nd- force=mass*acceleration 3rd- for every action there is an equal and opposite reaction
If springs are holding u p a box
2 springs holding box attached as 1 long spring- each holding entire weight of box 2 springs holding box at different ends of the box each spring holds 1/2 weight of the box
troposphere
20,000 ft at poles 60000 at equator
changing a percent to a decimal
4% is .04 the rule is to drop the % and move the decimal over TWO PLACES TO THE LEFT
A purchaser paid 17.16 for an article that had recently been increased in price by 4%. What was the price before the increase?
100-4=96 multiply 17.16 *.96=16.4736
hydrometer
uses floats to measure specific gravity. (weight of a liquid compared with weight of water. The liquid with the highest specific gravity will cause the float to rise higher in the glass tube.
cloest to the center
when driver wheel is present how will the adjacent wheels rotate
finding the square root of a number that is not a perfect square
use the nearest tenth: square root of 28? well square root of 25 is 5, so you can guess that 5.2, 5.2x5.2 is 27.04 and is less than 28, we can use 5.3x5.3 which is 28.09 rounded to the nearest tenth is 28!
ebb tide
when the tide falls after high tide
adding and subtracting mixed numbers
you must add the WHOLE numbers first, then add the fractions and find common denominator if need be.
adding & subtracting fractions
you must find the COMMON DENOMINATOR FIRST
problem
the long wolf does not support, the 2 diagonals carry it alone
in pulleys, which pulley will turn faster?
the small puller will turn faster than those larger than it
neap tide
those tides midway between spring tides that attain the least height
In a 3 hour examination of 320 questions, there are 40 mathematics problems. If twice as much time should be allowed for each mathematics problem as each of the other questions, how many minutes should be spent on he mathematics problems?
Let x = minutes to be spent on each problem 40*x + 1/2*x*280 = 180 solve for x, x = 1 minute plug back in to initial, 40*1= 40 minutes
vertex
POINT WHERE LINES MEET IN AN ANGLE
electrical theory
V=I*R finds voltage drop across a circuit
cirrocumulus
above 18k feet
Always move from
hot object to cold object
One pipe can fill a pool 1.25 times faster than a second pipe. When both pipes are opened, they fill the pool in five hours. How long would it take to fill the pool if only the slower pipe is used?
hours to complete job: fast pipe: f slow pipe: 1.25f together: 5 completed per hour: fast pipe: 1/f slow pipe: 1/1.25f together: 1/5 adding their labor: 1/f + 1/1.25f = 1/5 multiplying through by 5f: 5 + 5/1.25 = f 5 + 4 = f = 9 Then 1.25f = 11.25, so the slower pipe takes 11.25 hours.
where is the ozone layer?
in the higher end of the stratosphere
how do you increase the effort of the lever arm?
increase the length and enable a valve to blow off at a higher pressure. moving the weight further away will do this
4 stroke engine
intake compression combustion and exhaust
changing a decimal to a percentage
move the decimal two places to the RIGHT for example, .47=47% and .03=3%
water flows faster through what size area?
narrow areas than wider
can electricity flow through a circuit with a burned out bulb?
no but a voltmeter can bypass it if connected on both sides since it measures total voltage in a circut
if a weight hangs from a string does the length of the string matter?
no, the pull is exerted only by weight and string length doesn't matter
in a 2 pulley system, how much will the movable pulley move up?
only half the distance and spin half as much as the fixed pulley, even if they are the same diameter
Compressing air in a closed space will
decrease the volume and raise the temp
variation
difference between true bearing and magnetic bearing
fathometer
electronic device used in making deep sea soundings
what is kinetic energy?
energy in motion
n Factorial
find the product of every number between 1 and x multiplied together, i.e. f factorial means 5x4x3x2x1
Multiplying fractions
first multiply the numerators by each other then multiply the denominators by each other
dividing fractions
to divide you have to invert the second fraction and then change the division sign to a multiplication sign and solve as mutiplying
cumulonimbus
from near the ground to above 50k feet
decimal fractions
.7=7/10 or .07 is 7/100 etc
stratosphere
120000 ft 20 miles
mesophere
300000 ft 50 miles
Devices
Ammeter- measures current flow in a circuit Voltmeter- measures voltage Multimeter- measures both
high aspect ratio looks like
long and skinny wings
4 methods of determining position
piloting, dead reckoning, celestial navigation, electronic navigation
sextant
precision instrument used in celestial navigation to me sure angles
What is pressure?
pressure=force/area
Gear revolutions
r=D*R/d D: number of teeth on gear A R: revolutions of gear A d: number of teeth on gear B r: revolutions of gear B
mechanical advantage
radius of axle/radius of drum (use the RADIUS NOT THE DIAMTER)
aspect ratio
ratio of the distance between the wing tips of an airplane to its average wing width
wing load
ratio of wing surface area to aircraft weight
aircraft will take off on a treadmill
regardless of treadmill setting
low aspect ratio
short and stubby wings
what is potential energy?
stored energy in an object
Buoyancy
the deeper you go with an inflated ball, the more difficult it is to hold it under water. the deeper you go with that same ball, the more buoyant the ball is
Units
Charge= coulomb, C Current flow= ampere, A Power= volts*amperes
cumumlus
below 6k feet
cirrus
above 18k feet
micrometer
Sleeve section: horizontal cylindric shape; read as dollars and quarters Thimble section: vertical cylindric shape; read as cents added to the initial money^ the first part is contributed by the main scale on the sleeve the second part is contributed by the rotating vernier scale on the thimble (5+.5+.28=5.78mm)
Traveling / Gas mileage / average speed question
Take the gallons of gas used * miles per gallon to get total miles traveled Take miles traveled / average speed = hours (v = d/t)
A can complete a project in 20 days and B can complete the same project in 30 days. If A and B start working on the project together and A quits 10 days before the project is completed, in how many days will the project be completed?
Therefore, A would have completed x-10/20 th of the project and B would have completed x/30 th of the project. x-10/20+x/30=1; Solving for x, we get x = 18.
what kind of plane is an axe?
a wedge which is an inclined plane
Supplemental angle
adds up to 180 degrees
Complementary angle
adds up to 90 degrees
trailing edge
aft end of airfoil where airflow traveling over its surface meets airflow from below its surface
capstan
an apparatus used for hoisting weights, consisting of a vertical spool shaped cylinder that is roared manually or by machine and around which cable is wound
stratocumulus
below 6k feet
stratus
below 6k feet
Heat
convection-occurs in liquids and gases y circulating currents cause by a difference in density conduction-occurs in solids and stationary fluid depends on temp difference
I=Q/T
current=charge/time
camber
curvature of the top of a wing or airfoil
third class lever?
fulcrum is at one end and effort is between i.e. tongs, tweezers, fulcrum is in part of the tool
second class
fulcrum is at one end and load is in between, i.e. nutcracker, wheelbarrow fulcrum is in the wheel
A bridge crosses a river that is 1520 feet wide. One bank of the river holds 1/5 of the bridge and the other holds 1/6. How long is the bridge?
(1/6)*x + (1/5)*x + 1520 = x Common denominator: 5x + 6x + 45600 = 30x Solve for x = 2,400 feet long
4 quarts
1 gallon
8 pints
1 gallon
16 ounces
1 pound
2000 lbs
1 ton
What is a fixed single pulley?
1 with 2 strings, i.e. a flag pole
If a driver completes a trip of 120 miles at a rate of 30mph, at what rate would the driver have to travel on the return trip in order to average 40mph for the round trip?
30mph for 4 hours = 120 miles. So round trip is 240 miles. 240 miles @ 40mph would take 6 hours. She used up 4 hours on the way there, so she has to complete the last 120 miles in 2 hours. D=R*T, R=60mph
If 3 times x exceeds 1/3 of y by 9, which of the following is the equation that shows the relationship between x and y?
3x-1/3*y=9
A tank that holds 450 gallons of water can be filled by 1 pipe in 15 minutes, and emptied by another in 30. How long would it take to fill the tank if both pipes are open?
450 / 15 = 30 gallons per minute fill rate 450 / 30 = 15 gallons per minute empty rate 30 gpm - 15 gpm = 15 gpm with both pipes open so 450gallons/15gpm = 30 minutes
altocumulus
6k to 20k
altostratus
6k to 20k
percentages
7% is the same as 7/100 or 25% is the same as 25/100
air
78% Nitrogen, Oxygen 21%, Argon 1%, the rest is traces of Carbon Dioxide, hydrogen, and other rare gases you typically need oxygen if you fly above 10,000 ft*****
A field can be plowed by 9 machines in 5 hours. If 3 machines are broken and cannot be used, how many hours will it take to plow the field?
9*5 = 45 total machine hours to finish job 3 broken, so 6 will be used 45 / 6 = 7.5 hours
weight
=mass*gravity
Questions about discount price
Amount of discount / Original price = % of reduction reduction * 100 = final answer %
A naval detachment has enough rations to feed 16 people for 10 days. If 4 more people join the detachment, for how many fewer days will the rations last?
First get the total rations, 16*10 = 160. 4 more people = 20 people. So divide 160/20 = 8 days 8 is 2 less days.
A businesswoman spends 1/5 of her income for rent, and 3/8 of the remainder goes towards salary. How much does she have remaining.
First take 1/5 away from 1, giving her 4/5. Multiply 4/5 * 3/8 = 12/40 = 3/10. 3/10 is the final answer
How much pure acid must be added to 12 ounces of a 40% acid solution in order to produce a 60% acid solution?
P1*V1 + P2*V2 = P3*V3 P1*V1 would be X*1 P2*V2 is volume of first*percentage of first P3*V3 = (X+volume of first solution)*volume of final solve for X 100x + 480 = 60(12+x), x=6
take number of rods on the wheel, divide that from the needed contacts per minute. (ex. twice per second = 120 contacts per minute. 10 projection rods on wheel. 120/10=12. must rotate at 12 rpm.
RPM
Questions about how fast people can do a job together?If the first painter can do the entire job in twelve hours and the second painter can do it in eight hours, then (this here is the trick!) the first guy can do 1/12 of the job per hour, and the second guy can do 1/8 per hour. How much then can they do per hour if they work together?
Take each number of hours and use 1/x amount of hours. Example: To find out how much they can do together per hour, I add together what they can do individually per hour: 1/12 + 1/8 = 5/24.They can do 5/24 of the job per hour. Now I'll let "t" stand for how long they take to do the job together. Then they can do 1/t per hour, so 5/24 = 1/t. Flip the equation, and you get that t = 24/5 = 4.8 hours. 1/12 + 1/8 = 1/t 5/24 = 1/t 24/5 = t =4.8 hours
Pendulums
The one with the longer string takes the longest to complete 1 swing. The weight doesn't matter for swing time. If string length is the same, swing time is the same
What is a first class lever?
fulcrum is in the middle i.e. scissors or pliers
The rate of transfer is greater for the
greater temp difference
Rate of heat exchange is faster through objects of?
greater temperature difference
Salt in to water
increases the specific gravity of solution and lowers its freezing point
spring tide
large ride and fall of the tide at or soon after the new or full moon
compass deviation
the error of a magnetic compass due to local magnetism. it is dependent upon your heading; the difference between your desired grid or map heading and the heading you must follow due to effects of local magnetism