ASVAB Mechanical Comprehension Practice Test 235198 Results

Your Results Global Average
Questions 5 5
Correct 0 2.96
Score 0% 59%

Review

1

Connected gears of different numbers of teeth are used together to change which of the following charasteristics of the input force?

65% Answer Correctly

energy

force

torque

rotational direction
Solution

Connected gears of different numbers of teeth are used together to change the rotational speed and torque of the input force. If the smaller gear drives the larger gear, the speed of rotation will be reduced and the torque will increase. If the larger gear drives the smaller gear, the speed of rotation will increase and the torque will be reduced.

2

What is work?

60% Answer Correctly

The movement of an object by a force

Force per unit distance

The potential for exertion

Force per unit time
Solution

Work is accomplished when force is applied to an object: W = Fd where F is force in newtons (N) and d is distance in meters (m). Thus, the more force that must be applied to move an object, the more work is done and the farther an object is moved by exerting force, the more work is done. By definition, work is the displacement of an object resulting from applied force.

3 How much resistance could a 75 lb. effort force lift using a block and tackle pulley that has 4 ropes supporting the resistance?
81% Answer Correctly
900 lbs.
300 lbs.
150 lbs.
299 lbs.
Solution

The mechanical advantage (MA) of a block and tackle pulley is equal to the number of times the effort force changes direction. An easy way to count how many times the effort force changes direction is to count the number of ropes that support the resistance which, in this problem, is 4. With a MA of 4, a 75 lbs. effort force could lift 75 lbs. x 4 = 300 lbs. resistance.

4 If the radius of the axle is 3 and the radius of the wheel is 4, what is the mechanical advantage of this wheel and axle configuration?
36% Answer Correctly
-1
1
1
0
Solution

The mechanical advantage of a wheel and axle lies in the difference in radius between the inner (axle) wheel and the outer wheel. But, this mechanical advantage is only realized when the input effort and load are applied to different wheels. Applying both input effort and load to the same wheel results in a mechanical advantage of 1.

5

Assuming force applied remains constant, which of the following will result in more work being done?

53% Answer Correctly

moving the object with more speed

increasing the coefficient of friction

moving the object with more acceleration

moving the object farther
Solution

Work is accomplished when force is applied to an object: W = Fd where F is force in newtons (N) and d is distance in meters (m). Thus, the more force that must be applied to move an object, the more work is done and the farther an object is moved by exerting force, the more work is done.