ASVAB ASVAB-SECTION-3 Online Practice Questions and Exam Preparation

ASVAB ASVAB-SECTION-3 Online Questions & Answers

• Question 91:

  The amount of magnification that a machine produces is referred to as the __________.

  A. effort arm
  B. work
  C. mechanical advantage
  D. efficiency
  C. mechanical advantage

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  By using a machine, it is possible to multiply the amount of effort expended to get a job done. Mechanical advantage is the amount of magnification, or the ratio of load to effort.

• Question 92:

  A valve is used to perform which of the following functions?

  A. increase the temperature of a liquid
  B. control the flow of a liquid
  C. aid evaporation of a liquid
  D. decrease the density of a liquid
  B. control the flow of a liquid

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  Valves are placed in piping systems and can be opened or closed in order to control the flow of liquids or gasses.

• Question 93:

  The brakes on your car use the same force that stops your car if you just let it coast. This force is called ___________.

  A. velocity
  B. gravity
  C. friction
  D. newton
  C. friction

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  Friction is used to stop a car.

  The brakes rub against the wheel drum or the disc to cause the car to stop. This rubbing is creating friction.

• Question 94:

  If Block A, on which the lever is resting, is moved farther away from Block B __________.

  

  A. it will be harder to lift Block B but it will go higher
  B. it will be easier to lift Block B and it will go higher
  C. it will be harder to lift Block B and it will not be lifted to the same height
  D. it will be easier to lift Block B but it will not be lifted as high
  A. it will be harder to lift Block B but it will go higher

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  It will be harder to lift Block B but it will go higher.

  If Block A under the beam serving as the lever is moved away from Block B on top of the lever beam, the moment for the force exerted will increase, since the fulcrum is now closer to the force; this will make Block B harder to lift. However,

  the height to which Block B on the end of the lever beam can be raised increases the further away Block A is moved from Block B.

• Question 95:

  Springs are used for the following purposes EXCEPT ___________.

  A. to store energy for part of a mechanical cycle
  B. to force a mechanical component to maintain contact with another component
  C. to reduce shock or impact
  D. to increase the weight of a mechanism
  D. to increase the weight of a mechanism

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  Springs are used for all the listed purposes except to add weight.

• Question 96:

  Water flows into a container at a rate of 140 gallons per minute. The container has a small opening at the bottom that drains water at a rate of 1 gallon per second. How long will it take to fill the container to 240 gallons?

  A. 2 min
  B. 3 min
  C. 4 min
  D. Not enough information
  B. 3 min

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  The opening drains water at 1 gallon/second which is equivalent to 60 gallons/min. Therefore, the net gain of water is 140 gallons/min - 60/gallons/min = 80 gallons/min. To fill 240 gallons at a rate of 80 gallons/min will take 3 minutes.

• Question 97:

  The lift caused by an aircraft's wings is primarily due to ___________.

  

  A. a decrease in pressure on the upper side of the wing (A)
  B. a decrease in pressure on the bottom side of the wing B
  C. a vacuum created under the wing at point B
  D. an increase in pressure on the upper side of the wing (A)
  A. a decrease in pressure on the upper side of the wing (A)

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  When oncoming air meets the leading edge of the airfoil (wing), some of it goes over the top of the airfoil and some of it flows underneath. The air flowing over the top of the wing has to go further than the air underneath, because it must join together again with the air that flowed under the wing at the far (back) side of the wing ?physical laws act together to prevent or minimize vacuums in most cases.

• Question 98:

  Which material is best suited for use as a boat anchor?

  A. foam
  B. metal
  C. wood
  D. glass
  B. metal

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  Foam and wood float and would therefore make poor boat anchors. Glass is not strong enough to be used as a boat anchor.

• Question 99:

  

  What is the mechanical advantage of this pulley system?

  A. 6
  B. 4
  C. 3
  D. 2
  C. 3

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  In a pulley system, you calculate the mechanical advantage by counting up the number of supporting ropes/strands that support the weight. In this case, there are 3 supporting strands that support the load, so the mechanical advantage is 3.

• Question 100:

  

  In the figure above, for each complete revolution the cam makes, how many times will the valve open?

  A. 1
  B. 6
  C. 3
  D. 2
  C. 3

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  The valve will open each time a high point of the cam hits it. The cam has three high points, so the valve will open three times per revolution.