Take the following quiz to check your understanding of ASVAB Mechanical Comprehension topics. If you need a concept review, please read the study guides:

1. The diagram shows a class 1 lever. Which of the following is the same kind of lever?
1. A pair of tweezers
2. A pair of scissors
3. A wheelbarrow
4. A pair of tongs
2. The diagram shows a class 2 lever. Which of the following is the same kind of lever?
1. A seesaw
2. A pair of scissors
3. The human forearm
4. A wheelbarrow
3. When a mass of air expands, which of the following is most likely to happen?
1. The air warms up.
2. The air cools down.
3. The air stays at the same temperature.
4. The air contracts.
4. The diagram shows a class 3 lever. Which of the following is the same kind of lever?
1. A pair of tweezers
2. A wheelbarrow
3. A seesaw
4. A wedge
5. Which of the following would feel hottest to the touch if one end were placed in a pot of boiling water?
1. A wooden spoon
2. A metal fork
3. A plastic knife
4. A plastic cup
6. A lever lifts 300 lb with an effort of 60 lb. What is the mechanical advantage?
1. 3
2. 4
3. 5
4. 8
7. In a class 1 lever with an MA of 4, if the effort distance measures 8 ft, how long is the load distance?
1. 2 ft
2. 4 ft
3. 8 ft
4. 16 ft
8. Water is flowing into a tank at the rate of 180 gallons per minute. However, the tank has a leak, and water is leaking out at the rate of 2 gallons per second. How long will it take to add 120 gallons?
1. 1 min
2. 2 min
3. 3 min
4. 4 min
9. Water is flowing from a 3-inch pipe into a 1-inch pipe. Which statement is true?
1. Pressure is lower in the 3-inch pipe.
2. Pressure is higher in the 1-inch pipe.
3. More water is passing through the 3-inch pipe than through the 1-inch pipe.
4. The same amount of water is passing through every part of the piping system.
10. Gear A, with 18 teeth, meshes with gear B, which has 12 teeth. When gear A rotates 3 times, gear B will rotate
1. 3 times.
2. 4.5 times.
3. 6 times.
4. 9 times.
11. What is the mechanical advantage in this pulley system?
1. 2
2. 3
3. 4
4. 6
12. In the diagram, what can you tell about the load on posts A and B?
1. Post B carries more weight.
2. Post A carries more weight.
3. Post A carries no weight.
4. The load is equal on posts A and B.
13. Water is flowing through this pipe. Which statement is true?
1. Water is moving faster at point A than at point
2. Water pressure is equal at points A and B.
3. Water pressure is greater at point A than at point B.
4. Water pressure is greater at point B than at point A.
14. What is the advantage of using triangle shapes in constructing a bridge?
1. Triangles are sturdier than other shapes.
2. Triangles are very flexible.
3. Triangles are inexpensive to manufacture.
4. Triangles are attractive to look at.
15. Which formula will calculate the mechanical advantage of a lever?
3. Both A and B

1. B. In a class 1 lever, the fulcrum is between the effort and the load. Of the choices, only the pair of scissors has the same arrangement of elements. The tweezers (choice A) and tongs (choice B) are examples of class 3 levers. The wheelbarrow (choice C) is a class 2 lever.
2. D.In a class 2 lever, the fulcrum is at one end, the effort is at the other end, and the load is between the fulcrum and the effort. Of the choices, only the wheelbarrow has this arrangement of elements. The seesaw (choice A) and the scissors (choice B) are class 1 levers. The human forearm (choice C) is a class 3 lever.
3. B.Air is a gas, so according to the gas laws, when a mass of warm air expands, it will most likely cool down.
4. A.In a class 3 lever, the fulcrum is at one end, the load is at the other, and the effort is between the fulcrum and the load. Of the choices, only the tweezers have this arrangement of elements. The wheelbarrow (choice B) is a class 2 lever. The seesaw (choice C) is a class 1 lever. The wedge (choice D) is not a lever at all but an inclined plane.
5. B.Metal is a better conductor of heat than wood or plastic, so the metal fork would feel hottest to the touch.
6. C.MA = load/effort. 300/60 = 5
7. A.MA = effort distance/load distance. 4 = 8/load distance. 4 = 8/2. The load distance is 2 ft.
8. B.The leak of 2 gal/sec = 120 gal/min. Net gain is 60 gal/min, so it will take 2 minutes to add 120 gallons to the tank.
9. D.Because water cannot be compressed, the same amount of water must be flowing through both parts of the pipe system. This makes choice C incorrect. If the same amount of water is flowing through all parts of the system, then the water must be flowing faster in the 1-inch section, reducing pressure in that section. That makes choices A and B both incorrect.
10. B.The ratio of teeth is 18 to 12. Each turn of gear A will turn gear B 1.5 times. 1.5 × 3 = 4.5.
11. A.Count the supporting strands (the strands of rope that will be shortened as the load is lifted). There are two supporting strands, so MA = 2.
12. D.Since the load is centered between the posts, each post carries equal weight.
13. C.When fluid speed increases, pressure decreases. Because the same amount of water must be in these pipes, water must be moving faster at point B. Therefore pressure is lower at point B.
14. A.The only way to distort the form of a triangular- shaped structure is to break the legs or angles. That makes triangles sturdier than other structural shapes, which is a good reason to use triangle shapes when constructing a bridge.