ASTB Mechanical Comprehension
UPDATED ACTUAL Exam Questions and
CORRECT Answers
Which pulleys provide mechanical advantage? - CORRECT ANSWER - movable
Formula for gear revolutions - CORRECT ANSWER - r(revolutions) x d (number of teeth) =
RxD
Pulley mechanical advantage - CORRECT ANSWER - number of parts of the rope that act on
the load
Note about mechanical advantage: - CORRECT ANSWER - mechanical advantage is gained
by combining a fixed pulley with a moveable pulley or another fixed pulley of a different
diameter
What are hydrometers? - CORRECT ANSWER - They use floats to measure specific gravity
What is specific gravity? - CORRECT ANSWER - the weight of a liquid compared with the
weight of water. the liquid with the highest specific gravity will cause the float to rise higher in
the glass tube
The lower the density of the substance... - CORRECT ANSWER - ...the farther the
hydrometer will sink.
first class lever - CORRECT ANSWER - fulcrum in the middle (scissors, pliers)
second class lever - CORRECT ANSWER - fulcrum is at one end, load is in between
(nutcracker, wheelbarrow)
, third class lever - CORRECT ANSWER - fulcrum is at one end, effort is in between (tongs,
tweezers)
Which turns faster? small or big pulley? - CORRECT ANSWER - smaller pulley will turn
faster than those larger than it. it has to "keep up" and therefore turns faster.
mechanical advantage in pistons - CORRECT ANSWER - a2 x d2 = a1 x d1
(smaller D)/(bigger D) = mechanical advantage
axe is a... - CORRECT ANSWER - wedge, which is an inclined plane
Fulcrum Resistance Arm Info? - CORRECT ANSWER - the farther away the fulcrum is from
the resistance arm, the greater the amount of force that is required to lift the weight and the
higher the resistance arm will travel
Voltimeter? - CORRECT ANSWER - Measures total voltage in a circuit
Does electricity flow through burnt out bulbs? - CORRECT ANSWER - No, but a voltimeter
can bypass it if connected on both sides.
Series: current and voltage - CORRECT ANSWER - current is constant in series, voltage is
not
Parallel: current and voltage - CORRECT ANSWER - voltage is constant, current is not
Voltage formula - CORRECT ANSWER - V=I*R (voltage = current*resistance)
Which circuit usually has the greater resistance? - CORRECT ANSWER - The circuit with the
greater resistance is usually in series, because it forces the current through all resistors.
UPDATED ACTUAL Exam Questions and
CORRECT Answers
Which pulleys provide mechanical advantage? - CORRECT ANSWER - movable
Formula for gear revolutions - CORRECT ANSWER - r(revolutions) x d (number of teeth) =
RxD
Pulley mechanical advantage - CORRECT ANSWER - number of parts of the rope that act on
the load
Note about mechanical advantage: - CORRECT ANSWER - mechanical advantage is gained
by combining a fixed pulley with a moveable pulley or another fixed pulley of a different
diameter
What are hydrometers? - CORRECT ANSWER - They use floats to measure specific gravity
What is specific gravity? - CORRECT ANSWER - the weight of a liquid compared with the
weight of water. the liquid with the highest specific gravity will cause the float to rise higher in
the glass tube
The lower the density of the substance... - CORRECT ANSWER - ...the farther the
hydrometer will sink.
first class lever - CORRECT ANSWER - fulcrum in the middle (scissors, pliers)
second class lever - CORRECT ANSWER - fulcrum is at one end, load is in between
(nutcracker, wheelbarrow)
, third class lever - CORRECT ANSWER - fulcrum is at one end, effort is in between (tongs,
tweezers)
Which turns faster? small or big pulley? - CORRECT ANSWER - smaller pulley will turn
faster than those larger than it. it has to "keep up" and therefore turns faster.
mechanical advantage in pistons - CORRECT ANSWER - a2 x d2 = a1 x d1
(smaller D)/(bigger D) = mechanical advantage
axe is a... - CORRECT ANSWER - wedge, which is an inclined plane
Fulcrum Resistance Arm Info? - CORRECT ANSWER - the farther away the fulcrum is from
the resistance arm, the greater the amount of force that is required to lift the weight and the
higher the resistance arm will travel
Voltimeter? - CORRECT ANSWER - Measures total voltage in a circuit
Does electricity flow through burnt out bulbs? - CORRECT ANSWER - No, but a voltimeter
can bypass it if connected on both sides.
Series: current and voltage - CORRECT ANSWER - current is constant in series, voltage is
not
Parallel: current and voltage - CORRECT ANSWER - voltage is constant, current is not
Voltage formula - CORRECT ANSWER - V=I*R (voltage = current*resistance)
Which circuit usually has the greater resistance? - CORRECT ANSWER - The circuit with the
greater resistance is usually in series, because it forces the current through all resistors.
