OAR (MECHANICAL
COMPREHENSION)
What kinds of pulleys provide mechanical advantage - answer only moveable pulleys
what is the formula for gear revolutions - answer In the example below the DRIVER
gear is large than the DRIVEN gear. The general rule is - large to small gear means
'multiply' the velocity ratio by the rpm of the first gear. Divide 60 teeth by 30 teeth to find
the velocity ratio. Multiply this number (2) by the rpm (120). This gives an answer of
240rpm.
If A revolves at 120 revs/min what is B ?
(Remember large gear to small gear increases revs)
what does D, R, d, r stand for in the gear revolutions formula - answerD: # of teeth in
gear A
R: revolutions of gear A
d: number of teeth on gear b
r:revolutions of gear b
what do hydrometers do - answeruse floats to measure specific gravity
what is specific gravity - answerthe weight of a liquid compared with the weight of the
water
the liquid with the highest specific gravity will cause the float to do what - answerrise
higher in the glass tube
first class lever - answerfulcrum is in the middle (scissors, pliers)
second class lever - answerfulcrum is at one end, load is in between (nutcracker,
wheelbarrow)
third class lever - answerfulcrum is at one end, effort is in between (tongs, tweezers)
in pulleys which will turn faster - answerthe smaller pulley will turn faster than larger
ones because it has to keep up
formula for mechanical advantage in pistons - answera2*d2=a1*d1
COMPREHENSION)
What kinds of pulleys provide mechanical advantage - answer only moveable pulleys
what is the formula for gear revolutions - answer In the example below the DRIVER
gear is large than the DRIVEN gear. The general rule is - large to small gear means
'multiply' the velocity ratio by the rpm of the first gear. Divide 60 teeth by 30 teeth to find
the velocity ratio. Multiply this number (2) by the rpm (120). This gives an answer of
240rpm.
If A revolves at 120 revs/min what is B ?
(Remember large gear to small gear increases revs)
what does D, R, d, r stand for in the gear revolutions formula - answerD: # of teeth in
gear A
R: revolutions of gear A
d: number of teeth on gear b
r:revolutions of gear b
what do hydrometers do - answeruse floats to measure specific gravity
what is specific gravity - answerthe weight of a liquid compared with the weight of the
water
the liquid with the highest specific gravity will cause the float to do what - answerrise
higher in the glass tube
first class lever - answerfulcrum is in the middle (scissors, pliers)
second class lever - answerfulcrum is at one end, load is in between (nutcracker,
wheelbarrow)
third class lever - answerfulcrum is at one end, effort is in between (tongs, tweezers)
in pulleys which will turn faster - answerthe smaller pulley will turn faster than larger
ones because it has to keep up
formula for mechanical advantage in pistons - answera2*d2=a1*d1
