ASVAB PRACTICE TEST A

Part 8: Mechanical Comprehension (MC)

19 Minutes 25 Questions

3. Directions: In this section, you will be tested on your knowledge of mechanics and basic physics. Select the best answer for each question and mark the corresponding oval on your answer sheet.

4. A car rolls down a hill. It travels progressively faster because

   1. its potential energy is being converted into kinetic energy
   2. its kinetic energy is being converted to potential energy
   3. its energy is maximized
   4. its energy is minimized

5. When a ball is thrown into the air, it has its maximum potential energy when

   1. it leaves the hand of the person throwing it
   2. it enters the hand of the person catching it
   3. its velocity is zero
   4. its velocity is greatest

6. Objects that require more force to get them moving have greater

   1. momentum
   2. inertia
   3. torque
   4. pressure

7. Isaac Newton discovered that every particle in the universe is attracted to every other particle. This law is called Newton’s

   1. first law of motion
   2. third law of motion
   3. law of universal gravitation
   4. second law of motion

8. A 30N force is applied to 5 kg box. Assuming no friction, what is the acceleration gained by the box?

   1. 0.15 m/s²
   2. 0.6 m/s²
   3. 1.5 m/s²
   4. 6 m/s²

9. Compared to lifting a heavy box directly from ground level up to the top of a ramp, pushing the box up the ramp (neglecting friction) is doing:

   1. less work
   2. more work
   3. the same amount of work
   4. no work

10. All of the following statements about work are true EXCEPT

    1. force is a factor of work
    2. it is possible to get more work out of a machine than what is put in
    3. to do work, an object must be moved
    4. work can be measured in foot-pounds

11. A chisel is illustrated below. A chisel is an example of a(n)

    
    1. wedge
    2. first-class lever
    3. inclined plane
    4. wheel and axle

12. The difference between a wedge and an inclined plane is

    1. a wedge has a steeper slope than an inclined plane
    2. a wedge is made to move, whereas an inclined plane stays stationary
    3. a wedge stays stationary, whereas an inclined plane is made to move
    4. a wedge has less friction

13. Which post holds up the greater part of the load?

    

    1. post A
    2. post B
    3. both hold up the load equally
    4. answer cannot be determined based on information provided

14. Work and kinetic energy are both measured in

    1. kilograms
    2. meters per second
    3. joules
    4. newtons

15. The design of a screwdriver is based on which of the following simple machines?

    1. inclined plane
    2. wheel and axle
    3. first-class lever
    4. pulley

16. An increase in force accomplished through mechanical advantage is always accompanied by in distance moved.

    1. an increase
    2. a decrease
    3. no change
    4. an increase at times and a decrease at other times

17. The design of a prybar, as illustrated, is based on which of the following simple machines?

    

    1. first-class lever
    2. second-class lever
    3. third-class lever
    4. inclined plane

18. One horsepower is equal to how many watts?

    1. 550
    2. 746
    3. 10,000
    4. 100

19. In order to increase force with a first-class lever, the fulcrum should be

    1. moved toward where the effort is applied
    2. kept in the same position
    3. moved toward where the object is moved
    4. removed altogether

20. Which of the following statements is correct?

    1. The work put out by a simple machine can sometimes exceed the work put in.
    2. The work put out by a simple machine always exceeds the work put in.
    3. The work put out by a simple machine can never exceed the work put in.
    4. The work put in by a simple machine is equal and opposite of the work put in.

21. If a small gear drives a large gear, a takes place.

    1. mechanical advantage
    2. block and tackle
    3. torque multiplication
    4. reduction in rotational speed

22. A block and tackle, as shown below, utilizes

    

    1. a single pulley
    2. multiple pulleys
    3. only moveable pulleys
    4. only fixed pulleys

23. The force required by a person pulling on a rope using a single pulley to lift an object is equal to

    1. the weight of the object
    2. twice the weight of the object
    3. one half of the weight of the object
    4. the weight of the object divided by the diameter of the pulley

24. The design of a doorknob is based on which of the following simple machines?

    

    1. inclined plane
    2. wheel and axle
    3. first-class lever
    4. pulley

25. An astronaut’s mass is 30 kg on Earth. What is his mass on the moon?

    1. the same
    2. lower
    3. higher
    4. cannot be determined

26. In a gear train, torque and speed can be described as

    1. exactly the same
    2. directly proportional
    3. inversely proportional
    4. sometimes proportional

27. An object’s potential energy can be calculated using the formula

    1. PE = m × v²
    2. PE = m × v
    3. PE = m × g × ℎ
    4. PE = m × a

28. A child applies a 10N force to a large box. The box however, does not move. How much work has the child done?

    1. 0 J
    2. 5 J
    3. 10 J
    4. 100 J

If you finish before the time is up, you may check over your work on this part only.