ASVAB ASVAB Certifications ASVAB-SECTION-3 Questions & Answers

• Question 81:

  The force that acts in an upward direction on anything submerged in a liquid or a gas is called __________.

  A. friction

  B. viscous drag

  C. gravity

  D. buoyancy

  Correct Answer: D

  Buoyancy is the force that makes ships float and helium-filled balloons rise. This means that the force that acts in an upward direction on anything submerged in a liquid or a gas is called buoyancy.

• Question 82:

  Weight is directly proportional to the acceleration due to ___________.

  A. friction

  B. elastic recoil

  C. viscous drag

  D. gravity

  Correct Answer: D

  Weight is not a fixed property of an object; it varies with location.

  Your weight is slightly less at the North Pole than it is at the equator. Your weight is much less on the

  moon than on earth.

  Everything weighs less where the acceleration due to gravity is smaller.

  Weight is directly proportional to local acceleration due to gravity.

• Question 83:

  In the pulley system shown, which pulley will rotate the fastest?

  

  A. Pulley A

  B. Pulley B

  C. Pulley C

  D. They will all rotate at the same speed.

  Correct Answer: B

  Pulley B will rotate the fastest. Just like meshing gears, the smaller the pulley in a system, the fester it rotates.

• Question 84:

  In the illustration below, if Pulley A is rotating in the direction indicated, then Pulley C will __________.

  

  A. rotate in the same direction as Pulley B

  B. rotate in the same direction as Pulleys A and B

  C. rotate in the opposite direction of Pulleys A and B

  D. rotate in the same direction as Pulley A

  Correct Answer: D

  Pulley C will rotate in the same direction as Pulley A.

  Pulley A causes Pulley B to rotate in the opposite direction from Pulley A, and Pulley B causes Pulley C to

  rotate in the opposite direction from Pulley B. Since there are only two directions of rotation available.

  Pulley C's direction of rotation is the same as Pulley A.

• Question 85:

  If you drop something, the force acting on it is ____________.

  A. gravity

  B. friction

  C. elastic recoil

  D. equilibrium

  Correct Answer: A

  Gravity is the force that pulls things down whenever they are dropped. It is said that Isaac Newton "discovered" the concept of gravity as an identifiable force while sitting under an apple tree and the obvious happened. Gravity is created by the mass of the earth. The pull of gravity is much less (about one-sixth) on the moon than on earth.

• Question 86:

  As the central shaft in the illustration below spins faster in a clockwise direction, the balls labeled A and B will ___________.

  

  A. move outward and downward

  B. move outward and upward

  C. move up

  D. move down

  Correct Answer: B

  Centrifugal force from the spinning shaft, regardless of direction, will cause the balls to move outward, away from the shaft; the tension on the strings holding them will result in the balls moving upward.

• Question 87:

  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

  Correct Answer: C

  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 88:

  Force is something that can change the velocity of an object by making it __________.

  A. start or stop

  B. speedup

  C. slow down

  D. all of the above

  Correct Answer: D

  Force is something that can change the velocity of an object by making it start or stop, speed up, or slow

  down.

  This means that all the answers given are correct.

• Question 89:

  Which of the other gears is moving in the opposite direction from Gear 1?

  

  A. Gear 2

  B. Gear 3

  C. Both Gears 2 and 3

  D. Neither Gear 2 or 3

  Correct Answer: A

  Meshed gears turn in opposite directions.

  Gear 1 is turning clockwise; therefore. Gear 2 is turning counterclockwise (the opposite direction from Gear

  1) and Gear 3 is turning clockwise (the same direction as Gear l).

• Question 90:

  Cranks are used to __________.

  A. convert motion in a circle into motion in a straight line

  B. convert motion in a straight line into motion in a circle

  C. attach to rotating shafts to push separate pieces in a given direction

  D. transfer power between rotating shafts of different diameters

  Correct Answer: B

  Cranks are used to convert motion in a straight line into motion in a circle, such as in a bicycle's pedals and pistons in an automotive engine.