Education.com
Try
Brainzy
Try
Plus

# Mechanical Comprehension Questions for ASVAB Power Practice Problems (page 2)

By
Updated on Aug 12, 2011

### Answers

1. d.   w1 ×d1 = w2 ×d2. 102 pounds ×6 feet = 68 pounds ×d2. Solving for d2 gives 9 feet.
2. b.   The mechanical advantage of a ramp is determined by its length divided by the height. Since ramp B is much longer (and the slope is much shallower) it provides a greater mechanical advantage and thus less force is required to raise the barrel.
3. a.   A single fixed pulley offers no mechanical advantage. Pulleys are used at the top of flagpoles because they change the direction of force required to raise the flag.
4. b.   The force constant of the spring is 4 pounds ÷ 6 inches = pounds per inch. Using the equation, F = kx, we have 6 pounds = pounds per inch ×x. Solving for x gives 9 inches.
5. c.   The area of opening of a pipe is pi times the square of half the diameter. So, the area of pipe A is π(1)2 = πand the opening of pipe B is π(2)2 = 4π. The rate at which liquid flows out of the pipes is equal to the ratio of the area of their opening. A ÷ B = π÷ 4π = 0.25. Water flows out of pipe B four times faster than pipe A.
6. a.   The scale works by balancing the weight of an object on one side of the pivot point with objects of known weight on the other side.
7. c.   For an object to float, its weight must be equal to the weight of water it displaces. Steel is much denser than water; however, the overall density of the ship is decreased due to numerous inner rooms filled with air.
8. b.   If 9 full turns move the nut 0.75 inches, there are 9 turns ÷ 0.75 inches = 12 threads per inch.

9. b.   In this pulley system, the weight of the load is shared over 2 cables and so the mechanical advantage is 2.
10. a.   A glass bottle is the best insulator of the choices given. Thus, it will keep the beverage colder for a longer period of time. Metals such as aluminum are good conductors and will rapidly transfer heat.
11. b.   If gear 3 turns counterclockwise, it will lead its neighboring gears (2 and 4) to turn clockwise.
12. a.   Since pulley B is four times greater in circumference than pulley A, pulley A must rotate 4 times for every revolution of B. If A rotates at 60 rpm, then B will rotate at 60 rpm ÷ 4 = 15 rpm.
13. a.   Ice is a slippery surface, meaning that it has a very low coefficient of friction. An object sliding on ice will take longer to slow down than it will on the other surfaces.
14. c.   Each turn of the pedals will move the bike 54 ÷ 12 = 4.5 revolutions. If the bike is pedaled at 90 rpm, the rear wheel will rotate at 90 rpm × 4.5 revolutions = 405 rpm.
15. a.   A decrease in air pressure means that air is hitting the outside of the balloon with less force, meaning that the helium inside the balloon will expand.
16. c.   w1 × d1 = w2 × d2. Daniel is 10 feet away from the pivot point. 225 pounds × 4 feet = 10 feet × w2. Solving for w2 gives 90 pounds.
17. b.   Orientation B has the widest base and lowest center of mass compared to orientations A and C.
18. c.   The density of an object is unchanged when it is cut in half. Density = mass ÷ volume. If the object is cut in half, both the mass and volume are decreased by half, so the density will remain unchanged.
19. d.   The mechanical advantage (MA) of a ramp is determined by the length of the ramp, l, divided by the height gained, h. In this case, MA = = 27 feet ÷ 3 feet = 9. The force required to pull a 360-pound block up a ramp is 360 pounds ÷ 9 = 40 pounds.
20. a.   An object will float on top of a liquid if its density is less than the density of the liquid it is in and sink if its density is greater. In this case, the lead plug is denser than water and mercury, so it will sink to the bottom of the beaker.
21. c.   A pulley system of this type has a mechanical advantage of 2. So if Keiko can pull a rope with 120 pounds of force, she will be able to lift a weight of 120 pounds × 2 = 240 pounds.
22. c.   w1 × d1 = w2 × d. 450 pounds ×3 feet = w2 ×9 feet. Solving for w2 gives 150 pounds.
23. b.   After 1 hour, the first man has traveled 25 miles and the second has traveled 15 miles. 25 miles – 15 miles = 10 miles.
24. a.   The mechanical advantage (MA) of a ramp is equal to the ratio of ouput force (280 pounds) to input force (70 pounds). It is also equal to the length of the ramp (16 feet) divided by the height gained by the ramp (x feet). The MA is 280 pounds ÷ 70 pounds = 4. So, we know that the length of the ramp (16 feet) divided by the height must equal 4 as well. The height of the ramp must be 4 feet.
25. d.   A pulley system of this type has a mechanical advantage of 2. So, if Maria can pull a rope with 100 pounds of force, she will be able to lift a weight of 100 pounds × 2 = 200 pounds.
View Full Article
Add your own comment