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# Mechanical Comprehension Overview for ASVAB Power Practice Problems

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Updated on Aug 24, 2011

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. In the diagram, Kenneth wants to balance two blocks on either side of a lever. One block weighs 27 pounds and the other weighs 24 pounds. If the 27-pound block is 4 feet to the left of the pivot point, how far to the right of the pivot point should the 24-pound block be placed?
1. 4.5 feet
2. 7 feet
3. 4 feet
4. 8.5 feet
2. If the rope on the end of this pulley system is pulled with 160 pounds of force, what is the maximum weight that can be lifted?
1. 640 pounds
2. 480 pounds
3. 320 pounds
4. 80 pounds
3. A beaker is filled with mercury and water. Mercury is a liquid with a density of 8 g/cm3 and water has a density of 1 g/cm3. If a penny with a density of 5 g/cm3 is dropped into the beaker, where will it settle?
1. at the bottom of the beaker
2. in the middle of the mercury layer
3. in between the mercury and water layers
4. on top of the water layer
4. A 240-pound block is being pulled up an incline by a pulley. The incline is 20 feet long and rises 5 feet. Neglecting friction, how much force is necessary to move the block up the incline?
1. 60 pounds
2. 100 pounds
3. 260 pounds
4. 240 pounds
5. A jack is able to lift a 3,000-pound car using only 50 pounds of force. What is the mechanical advantage of the jack?
1. 4
2. 60
3. 600
4. 2,950
6. The tires of a car are filled in a garage to a pressure of 35 pounds per square inch. Driving the car to a hot desert will have what effect on the tires?
1. Their pressure will increase.
2. Their pressure will decrease.
3. Their weight will increase.
4. Their weight will decrease.
7. A crane raises its arm using a powerful cable attached to the main body. Which cable position offers the greatest mechanical advantage?
1. A
2. B
3. C
4. They all offer the same advantage.
8. Two scales are connected by a plank weighing 2 pounds. A 12-pound block is placed directly in between the two scales. How many pounds will Scale 1 read?
1. 7 pounds
2. 10 pounds
3. 12 pounds
4. 14 pounds
9. A force of 9 pounds stretches a spring 3 inches. How far will the spring move under 12 pounds of force?
1. 3 inches
2. 4 inches
3. 6 inches
4. 36 inches
10. A solid object will float on water when
1. it is less dense than water.
2. it is more dense than water.
3. it has a large surface area.
4. it has a small surface area.
11. A nut travels 1.25 inches after 15 turns of the screw. How many threads per inch does the screw have?
1. 10
2. 12
3. 15
4. 20
12. Using the pulley system shown above, how much force is required to lift a 200-pound load?
1. 50 pounds
2. 100 pounds
3. 200 pounds
4. 400 pounds
13. Which material expands most when heated?
1. wood
2. steel
3. glass
4. rubber
14. Gear 1 has 12 teeth and gear 2 has 9. If the gear 1 turns at 30 rpm, how fast will gear 2 turn?
1. 20 rpm
2. 30 rpm
3. 40 rpm
4. 60 rpm
15. A 300-pound barrel is being supported on an incline.The incline is 18 feet long and rises 6 feet. How much force is necessary to prevent the barrel from rolling down?
1. 50 pounds
2. 100 pounds
3. 150 pounds
4. 300 pounds
16. A single-speed bicycle has a front chain ring with 55 teeth. The back gear has 11 teeth. If the bicycle is pedaled for 80 rpm, how many complete revolutions will the rear wheel make in 30 seconds?
1. 40 revolutions
2. 80 revolutions
3. 200 revolutions
4. 400 revolutions
17. 400 revolutions
1. Helium is less dense than air.
2. Helium is a noble gas.
3. Helium is hotter than air.
4. Helium is colder than air.
18. The pulley system shown in the figure offers what advantage?
3. a change in the direction of force
19. If gear 4 turns clockwise, which other gear(s) will also turn counterclockwise?
1. 1 only
2. 2 only
3. 3 only
4. 1 and 3
20. Two cylindrical pipes are used to drain a tank. Pipe A has a diameter of 2 inches and pipe B has a diameter of 6 inches. If there is equal water pressure inside the tank, how much more water will flow out of pipe B than pipe A?
1. The same amount will flow out of both pipes.
2. Three times more will flow out of pipe B.
3. Six times more will flow out of pipe B.
4. Nine times more will flow out of pipe B.
21. Steve goes on a run at 8 mph and travels 14 miles. How long did Steve run?
1. 1 hour 15 minutes
2. 1 hour 30 minutes
3. 1 hour 45 minutes
4. 2 hours
22. A 600-pound block is being pulled up a 15-foot incline. Neglecting friction, if 200 pounds of force is necessary to move the block up the incline, how tall is the incline?
1. 4 feet
2. 10 feet
3. 5 feet
4. 15 feet
23. In the diagram, Paul wants to lift a 90-pound block using a lever. If the block is 20 feet from the pivot point and Paul is 15 feet from the pivot point, how much force must he apply to lift the block?
1. 120 pounds
2. 450 pounds
3. 20 pounds
4. 90 pounds
24. A helium balloon is released from the ground and quickly rises 2,000 feet. What will happen to the balloon?
1. The balloon will become heavier.
2. The balloon will become lighter.
3. The size of the balloon will increase.
4. The size of the balloon will decrease.
25. Pulley A has 1.5 times the circumference of pulley B. If pulley A rotates counterclockwise at 30 revolutions per minute (rpm), how fast and in what direction will pulley B rotate?
1. 30 rpm clockwise
2. 30 rpm counterclockwise
3. 45 rpm clockwise
4. 45 rpm counterclockwise