Mechanical Comprehension Review for ASVAB Power Practice Problems

These mechanical comprehension practice questions are based on the actual ASVAB. Take this quiz to see how you would do if you took the exam today and to determine your strengths and weaknesses as you plan your study schedule.

Time: 19 minutes

1. A 250-pound weight is being lifted using the pulley system shown here. How much force is necessary to lift the weight?
   1. 50 pounds
   2. 100 pounds
   3. 125 pounds
   4. 250 pounds
2. When a mercury thermometer is placed in hot liquid, mercury will travel up the thermometer to provide an accurate temperature reading. Why does mercury rise in a thermometer when it is exposed to heat?
   1. Heat causes mercury to expand.
   2. Mercury is repelled by heat.
   3. Heat causes mercury to contract.
   4. Air bubbles push mercury up the thermometer.



3. In the diagram, Holly wants to lift a 120-pound block using a lever. If the block is 11 feet from the pivot point and Holly is 6 feet from the pivot point, how much force must she apply to lift the block?
   1. 220 pounds
   2. 66 pounds
   3. 120 pounds
   4. 720 pounds



4. The vertical motion of a piston is transferred to rotational motion at the crank. Based on the figure, what description best describes the position and direction of the piston when the crank arm is pointing downward?
   1. far left and stationary
   2. in the center and moving to the left
   3. in the center and moving to the right
   4. far right and stationary
5. Ian goes on a trail run and covers 12 miles in 1.5 hours. How fast was Ian running?
   1. 6 mph
   2. 8 mph
   3. 10 mph
   4. 18 mph



6. A 300-pound block is being pulled up an incline by a pulley. The incline is 25 feet long and rises 10 feet. Neglecting friction, how much force is necessary to move the block up the incline?
   1. 120 pounds
   2. 250 pounds
   3. 300 pounds
   4. 35 pounds



7. A force of 10 pounds is required to move a spring 8 inches. How far will the spring stretch under 15 pounds of force?
   1. 12 inches
   2. 14 inches
   3. 16 inches
   4. 18 inches
8. If 18 full turns are required to move a nut 1.2 inches, how many threads per inch does the screw have?
   1. 10
   2. 12
   3. 15
   4. 20
9. Using a lever, a man is able to lift a 120-pound load with only 40 pounds of force. What is the mechanical advantage of the lever?
   1. 
   2. 3
   3. 20
   4. 80



10. How much force is required to lift a 300-pound weight using the pulley system shown above?
    1. 75 pounds
    2. 100 pounds
    3. 150 pounds
    4. 900 pounds



11. If gear 1 turns clockwise, which other gears, if any, will also turn clockwise?
    1. 2 only
    2. 3 only
    3. 2 and 4
    4. None
12. When a submarine dives, it fills its ballast tanks with water, causing all the following EXCEPT
    1. the density of the submarine to increase.
    2. the buoyancy of the submarine to decrease.
    3. the weight of the submarine to increase.
    4. the volume of the submarine to increase.



13. Pulley system A offers no mechanical advantage, whereas pulley system B has a mechanical advantage of 2. In pulley system A, if the rope is pulled 10 feet, the hook will rise 10 feet. How many feet of rope must be pulled to raise the hook in pulley system B by 10 feet?
    1. 5 feet
    2. 10 feet
    3. 15 feet
    4. 20 feet



14. Three trucks are parked on an incline. Their centers of gravity are marked by dots. Which truck is most likely to tip over?
    1. truck A
    2. truck B
    3. truck C
    4. All trucks are stable.



15. The cable supporting the arm of the crane is attached to the arm in four different positions. In which position is the cable strained the most?
    1. cable A
    2. cable B
    3. cable C
    4. cable D
16. A steel block has a density of 0.3 pounds per cubic inch. Its dimensions are 2" × 2" × 5". What is the weight of the block?
    1. 6 pounds
    2. 10 pounds
    3. 20 pounds
    4. 27 pounds



17. In the diagram, Talia wants to lift a 90-pound block using a lever. If the block is 10 feet from the pivot point and Talia is 8 feet beyond that, how much force must she apply to lift the block?
    1. 45 pounds
    2. 80 pounds
    3. 90 pounds
    4. 50 pounds
18. Which material is best suited for building a raft?
    1. metal
    2. wood
    3. glass
    4. concrete
19. A single-speed bicycle has a front chain ring with 48 teeth and a back gear with 12 teeth. If the bicycle is pedaled at 90 rpm, how fast will the rear wheel turn?
    1. 15 rpm
    2. 90 rpm
    3. 180 rpm
    4. 360 rpm



20. Which of the following pulley systems offers the least mechanical advantage?
    1. A
    2. B
    3. C
    4. They all offer the same advantage.



21. In the diagram, two blocks are balanced on either side of a lever. One block weighs 50 pounds and the other weighs 100 pounds. If the 50-pound block is 8 feet to the left of the pivot point, how far to the right of the pivot point is the 100 pound block?
    1. 2 feet
    2. 4 feet
    3. 8 feet
    4. 16 feet



22. What is the mechanical advantage of the pulley system shown here?
    1. 1
    2. 2
    3. 3
    4. 4
23. Which of the following is heaviest?
    1. 1 cubic foot of water
    2. 1 cubic foot of lead
    3. 1 cubic foot of wood
    4. 1 cubic foot of ice



24. Pulley A has 2.5 times the circumference of pulley B. If pulley A rotates at 50 revolutions per minute (rpm), how fast must pulley B rotate?
    1. 20 rpm
    2. 50 rpm
    3. 125 rpm
    4. 250 rpm



25. If gear 3 turns counterclockwise, which other gear(s), if any, will turn clockwise?
    1. 1 and 5
    2. 2 and 4
    3. All will turn clockwise.
    4. None will turn clockwise.