Part 8: Mechanical Comprehension (MC)

19 Minutes 25 Questions

  1. 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.

  2. The force of friction between two surfaces moving past each other DOES NOT depend on

    1. the normal force
    2. the nature of the surfaces in contact with each other
    3. the area of the surfaces in contact with each other
    4. the speed with which the surfaces are moving past each other

  3. The formula for work is

    1. w = m × v
    2. w = m × g × h
    3. w = m × a
    4. w = F × d

  4. A small pulley drives a large pulley with a belt. Which of the following statements about this arrangement are true?

    1. The pulleys turn in opposite directions.
    2. The smaller pulley turns faster.
    3. Speed output is greater than the input.
    4. The smaller pulley is above the larger pulley.

  5. Any work that is done to accelerate an object at rest to speed v will be converted into the kinetic energy of that object. This principle is known as

    1. the work-energy theorem
    2. gravitational potential energy
    3. the principle of conservation of mechanical energy
    4. Newton’s second law

  6. Performing work at the rate of 1 joule per second is the same as expending

    1. 100 foot-pounds
    2. 10 psi
    3. 1 meter per second
    4. 1 watt of power

  7. All of the following statements about liquids are true EXCEPT

    1. liquids are practically incompressible
    2. liquids can be used to transmit force
    3. all liquids are good lubricants
    4. liquids conform to the shape of their container

  8. A crate with a weight of 250 N is resting on a rough, horizontal surface with a coefficient of static friction of 0.8. What will happen if an applied horizontal force of 200 N acts on the crate?

    1. The crate will move and continually accelerate while the force acts.
    2. The crate will move at a constant speed.
    3. The crate will not move.
    4. The crate will move but then decelerate back to rest as friction increases.

  9. If 100 pounds of force are applied over an area of 2 square inches, the pressure would be

    1. 5 psi
    2. 50 psi
    3. 100 psi
    4. 200 psi

  10. The advantage gained by the use of a mechanism in transmitting force is known as

    1. pressure
    2. hydraulics
    3. torque multiplication
    4. mechanical advantage

  11. The point that the lever pivots on is the

    1. gear
    2. torque
    3. fulcrum
    4. axle

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

    1. 0.17
    2. 6
    3. 15
    4. 150

  13. When a net force acts on an object,

    1. the object will slow to a stop
    2. the force will give the object a cumulative force
    3. the object will accelerate in the direction of the net force
    4. constant speed is impossible

  14. If pulley X turns in a clockwise direction, in which direction will pulley Y turn?

    image
    1. clockwise only
    2. counterclockwise only
    3. either clockwise or counterclockwise
    4. the direction cannot be determined based on the information provided

  15. The illustration below represents

    image
    1. a fixed pulley
    2. a moving pulley
    3. a rear axle
    4. a pendulum

  16. In order for a piston with a total surface area of 10 square inches to support 100 pounds, how much pressure will have to be applied?

    1. 1,000 psi
    2. 50 psi
    3. 10 psi
    4. 5 psi

  17. Given the following forces acting on a block, what are the net or resultant forces? (Assume that “left” means your left.)

    image
    1. 80 N to the right and 10 N down
    2. 80 N to the left and 10 N down
    3. 20 N to the left and 10 N down
    4. 20 N to the right and 10 N down

  18. Given a block and tackle with four ropes to lift a load one foot, barring friction, what is the mechanical advantage gained?

    image
    1. 24:1
    2. 10:1
    3. 8:1
    4. 4:1

  19. A child’s teeter-totter, of the sort shown below, is an example of which kind of lever?

    image
    1. first-class
    2. second-class
    3. third-class
    4. fourth-class

  20. A hockey puck slides across frozen ice. The puck will eventually slow to a stop because of

    1. wind drag
    2. gravity
    3. sliding frictional force
    4. inertia

  21. What is being applied to the bolt as it is being tightened?

    image
    1. torque
    2. friction
    3. kinetic energy
    4. gear ratio

  22. When tightening a fastener, if one uses a wrench that is 1 foot long, and applies a force of 100 pounds to the end of the wrench, of torque is being applied.

    1. 10 foot-pounds
    2. 100 foot-pounds
    3. 1,000 foot-pounds
    4. 10,000 foot-pounds

  23. Given the following pulley system, suppose a person is holding the other end of the rope, so that the box is stationary and the system is in equilibrium. What is the Tension force T that develops in the rope?

    image
    1. 10 N
    2. 25 N
    3. 50 N
    4. 100 N

  24. Neglecting friction, the mechanical advantage provided by a block and tackle is equal to

    1. the number of pulleys used in the block and tackle
    2. half of the number of pulleys used in the block and tackle
    3. twice the number of pulleys used in the block and tackle
    4. the diameter of the pulleys divided by the number of pulleys used in the block and tackle

  25. The symbol g, according to Newtonian laws, refers to

    1. acceleration due to gravity
    2. mass, in grams
    3. the Earth’s surface
    4. the ground

  26. The fulcrum is

    1. the location that the force is applied to a lever
    2. the location that the object is applied to a lever
    3. the pivot point of a lever
    4. the distance from the pivot point of a lever to the location the force is applied to the lever