Questions regarding how fast people can do a job together
Time actually needed / Time can do the job alone = 1
Product has been discounted to a new price, what is the percent reduction?
Old price - new price
Difference / old price
multiply numerator by 100, divide
You know details of one gear
How many revolutions of other gear?
r = (D*R)/d
#of teeth gear A * # revolutions of gear A / # teeth gear B
Specific Gravity
Weight of a liquid vs Weight of water
1st Class lever
Fulcrum in the middle
Scissors, Pliers
2nd class lever
Fulcrum at one end, load in between
Nutrcracker, Wheelbarrow
3rd class lever
Fulcrum at one end, effort in between
Tongs, Tweezers
Smaller pulley turns ____ than larger pulley
faster
Pioneer 10
First US craft to explore outer solar system
Characteristics of warm front
Steady, long periods of rain
Fog
Atmospheres: Lowest to highest
Troposphere
Stratosphere
Mesosphere
Thermosphere/Ionosphere/Aurora
Troposphere
20k feet at poles
60 k feet at equator
Stratoshere
120k ft (20 miles)
Mesosphere
300k ft (50 miles)
Boundary between Tropo and Stratosphere
Tropopause
Ozone layer
Located at higher end of stratosphere
You generally need oxygen if flying above
10k ft
Air composition
78% Nitrogen
21% Oxygen
1% Argon
Rest is CO2 and other rare gasses
An axe is classified as a
Wedge (Inclined Plane)
The farther away the fulcrum is from the resistance arm
more force is required to lift the load
higher resistance arm will travel
Current is _____ in a series
constant
Voltage is not.
Voltage is _____ in parallel circuits
constant.
Current is not
Formula for Voltage
V = I * R
I: Current
2 pulley system: movable and fixed pulley
Movable pulley will only move half the distance
Movable pulley will only spin half as much as fixed pulley
Finding RPM
Needed contacts per minute / # of rods on wheel
Pendulums
Swing weight makes no difference
Speed is dependent upon length of string
If you place an object evenly on 2 scales, each scale will
read half of the total weight.
True
4-stroke engine
Intake
Compression
Combustion
Exhaust
Pressure formula
Force / Area
Momentum Equation
Force * Distance
Ammeter
Measures current
Multimeter
Measures current, volt
Vise M.A.
(2*pi*length of handle) / pitch of thread
1 cup = _ oz
8
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?
1. Get the number of total rations available: 16 x 10 = 160 rations
2. 4 people + 16 people: 20 people
3. 160 rations divided amongst 20 people: 8 days
4. 8 days is 2 less than 10 days
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?
1. 9 machines in 5 hours: 45 machine hours
2. 3 machines broken: 6 working
3. 45/6: 7.5 hours
Lever Rules
I. : MA (leverage) increases with length of lever arm, or placement of fulcrum
II. Closer fulctrum to load: higher MA
III. A lever arm in balance: forcexlength = forcexlength on both sides
Boyle's Law
High volume: Low Pressure
High Pressure: Low Volume
Charles' Law
If gas is at constant pressure,
High volume: high temperature
Example: Heating gas doubles its temperature and volume
Bernoulli's Principle
As velocity of a fluid increases, pressure decreases
