ASVAB Mechanical Comprehension Practice Test 913866 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.32
Score	0%	66%

Review

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

53% Answer Correctly

	moving the object farther
	moving the object with more speed
	increasing the coefficient of friction
	moving the object with more acceleration

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.

For any given surface, the coefficient of static friction is ___________ the coefficient of kinetic friction.

54% Answer Correctly

	lower than
	opposite
	equal to
	higher than

Solution

For any given surface, the coefficient of static friction is higher than the coefficient of kinetic friction. More force is required to initally get an object moving than is required to keep it moving. Additionally, static friction only arises in response to an attempt to move an object (overcome the normal force between it and the surface).

Potential energy is energy that has the potential to be converted into what?

80% Answer Correctly

	power
	heat
	work
	kinetic energy

Solution

Potential energy is the energy of an object by virtue of its position relative to other objects. It is energy that has the potential to be converted into kinetic energy.

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

65% Answer Correctly

	force
	rotational direction
	torque
	energy

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.

5 How much resistance could a 120 lb. effort force lift using a block and tackle pulley that has 4 ropes supporting the resistance?

81% Answer Correctly

	480 lbs.
	240 lbs.
	483 lbs.
	720 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 120 lbs. effort force could lift 120 lbs. x 4 = 480 lbs. resistance.