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ASVAB Mechanical Comprehension

Terms in this set (37)

force
mass × acceleration
vector quantities
forces that has both size and direction
equilibrium
a stable situation in which forces cancel one another
velocity
the speed and direction of a moving object
acceleration
the rate at which velocity changes
pressure
force (in pounds) ÷ area (in inches)
work
force × distance
tension is measured in
pounds-force or newtons
work is measured in
foot-pounds
power
work ÷ time
power is measured in
horsepower (hp)
1 horsepower
33,000 foot-pounds per minute or 550 foot-pounds per second
mechanical advantage
when a machine multiplies the force you use
mechanical advantage
resistance ÷ effort = output force ÷ input force
fulcrum
point of support to reduce resistance and multiply the effect of effort
resistance arm
the part of a lever that applies a force on an object
effort arm
the part of a lever that you apply an input effort force to.
to determine how much a lever reduces the amount of effort needed to do work
length of effort arm ÷ length of resistance arm = resistance force ÷ effort force
mechanical advantage of using a lever
effort arm ÷ resistance arm
mechanical advantage of using a ramp
length of ramp ÷ height of ramp = weight of object being moved ÷ force required to move object
block and tackle pulleys
make lifting heavy objects easier or change the direction of the pull
a simple pulley
force must equal the weight of the object
gears
used to change direction, increase or decrease speed, or increase or decrease force
if you have an even number of gears connected in a series
the first and last gear turn in opposite directions
if you have an odd number of gears connected in a series
the first and last gear turn in the same direction
number of teeth
the speed at which a gear rotates depends on the ______
bevel gears
used to connect gears that have shafts (that aren't parallel to one another) at different angles
drive other pulleys
when connected by a system of belts, pulley can do what?
diameter of the pulley in relation to the diameter of the pulley that's driving it
how fast a pulley rotates depends of what?
wheel and axle
multiplies the effort used producing a greater force
wheel and axle
are fixed together and turn at the same time; ex. using a steering wheel
wheel and axle mechanical advantage
the relationship between the radius of the wheel and the radius of the area to which force is being applied
pitch
the distance between the ridges of the spiral (on the screw of a vise) is called the _____ of the thread
greater
the ____ the pitch of the thread, the farther the jaws of the vice move for each revolution of the handle
more
larger pitches require ____ force to rotate the handle than screws with smaller pitches do
hydraulic jack
uses a nearly incompressible liquid, such as oil, to exert force in order to move an object
mechanical advantage of a hydraulic jack
the ratio between the diameters of the two cylinders
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