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ASTB MECHANICAL COMPREHENSION EXAM QUESTIONS
Actual Qs and Ans - Expert-Verified Explanation -Guaranteed passing score -67 Questions and Answers
-Format: Multiple-choice / Flashcard
Question 1: wheel and axle
Answer:
one of six simple machines identified by renaissance scientists drawing from Greek texts on technology
Question 2: bar with weights on string
Answer:
if weights hang from a string attached to a bar, less pull is exerted by the weight of less weight. the length of string doesn't matter.
Question 3: Driver wheel and adjacent wheels
Answer:
if a driver wheel is present, the adjacent wheels will rotate according to how close to the center the driver wheel makes contact with them. the closer to the center, the faster it will move.
Question 4: formula for moment
Answer:
moment = force x distance; moment of force is the tendency of a force to twist or rotate an object (see torque for details). important, basic concept in engineering and physics
Question 5: how does narrow/wider affect amount of flow?
Answer:
the same amount of water will flow through the smaller and larger part of the pipe in a given time
Question 6: ammeter
Answer:
measures current flow in a circuit
Question 7: what happens with object on 2 scales?
Answer:
if placed evenly, each scale will read half of the total weight.
Question 8: when is rate of exchange faster?
Answer:
it is faster through objects of greater temperature difference
Question 9: what happens when you compress air?
Answer:
will decrease the volume and raise the temperature
Question 10: Voltage formula
Answer:
V=I R (voltage = current resistance)
Question 11: When is rate of transfer of heat greatest?
Answer:
greatest when the greater the temp difference
Question 12: Which circuit usually has the greater resistance?
Answer:
The circuit with the greater resistance is usually in series, because it forces the current through all resistors.
Question 13: to find a necessary rpm
Answer:
take number of rods on the wheel, and divide by the number of contacts per minute (for example, twice per second = 120 contacts per minute. 10 projection rods on wheel. 120/10 = 12. must rotate at 12 rpm)
Question 14: Vise mechanical advantage
Answer:
ideal MA = (2 pie length of handle)/(pitch of thread)
Question 15: Power (electrical theory)
Answer:
power = volts * amperes
Question 16: Newtons Third Law
Answer:
for every action there is an equal and opposite reaction
Question 17: What is specific gravity?
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
Question 18: Formula for gear revolutions
Answer:
r(revolutions) x d (number of teeth) = R x D
Question 19: What are hydrometers?
Answer:
They use floats to measure specific gravity
Question 20: find voltage
Answer:
V=I*R (find voltage drop across a circuit or single resistor)
Question 21: direct current
Answer:
flows continuously in the same direction
Question 22: kinetic and potential energy
Answer:
potential - energy stored in an object kinetic - energy in motion (when you lift a heavy object, you exert energy which later will become kinetic energy when the object is dropped). the higher something is lifted, the more potential energy is produced; thus, a greater kinetic energy is produced if something is dropped Question 23: Note about mechanical advantage:
Answer:
mechanical advantage is gained by combining a fixed pulley with a moveable pulley or another fixed pulley of a different diameter
Question 24: voltmeter
Answer:
measures voltage
Question 25: what happens to weight distribution with springs holding up a box?
Answer:
- springs holding the box attached as 1 longer spring? they are each holding the entire weight of the
- springs holding the box at different ends of the box? each spring holds 1/2 of the weight of the box
box
Question 26: 4 stroke engine
Answer:
intake, compression, combustion, exhaust
Question 27: axe is a...
Answer:
wedge, which is an inclined plane
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