ASVAB Mechanical Comprehension Practice Test 65265 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.19
Score	0%	64%

Review

Normal force is generally equal to the __________ of an object.

61% Answer Correctly

	weight
	density
	mass
	coefficient of friction

Solution

Normal force arises on a flat horizontal surface in response to an object's weight pressing it down. Consequently, normal force is generally equal to the object's weight.

Gear ratio indicates which of the following about two connected gears?

59% Answer Correctly

	mechanical advantage
	power conversion
	efficiency
	work done

Solution

The mechanical advantage (amount of change in speed or torque) of connected gears is proportional to the number of teeth each gear has. Called gear ratio, it's the ratio of the number of teeth on the larger gear to the number of teeth on the smaller gear. For example, a gear with 12 teeth connected to a gear with 9 teeth would have a gear ratio of 4:3.

The mechanical advantage of a wheel and axle is equal to the:

61% Answer Correctly

	length of the axle
	ratio of the diameters of the wheels
	difference in the lengths of the axles
	difference in the diameters of the wheels

Solution

A wheel and axle uses two different diameter wheels mounted to a connecting axle. Force is applied to the larger wheel and large movements of this wheel result in small movements in the smaller wheel. Because a larger movement distance is being translated to a smaller distance, force is increased with a mechanical advantage equal to the ratio of the diameters of the wheels. An example of a wheel and axle is the steering wheel of a car.

4 If input effort is 900 ft⋅lb, what output effort will be produced by a machine with a mechanical advantage of 8?

79% Answer Correctly

	7200 ft⋅lb
	1800ft⋅lb
	28800ft⋅lb
	3600ft⋅lb

Solution

Mechanical advantage is the ratio of output force to input force and tells us by how many times a machine multiplies input effort. So, a machine with a mechanical advantage of 8 will multiply an input effort of 900 ft⋅lb by 8 to produce an output effort of 7200 ft⋅lb.

What is the first step to solving a problem where multiple forces are acting on an object?

61% Answer Correctly

	calculate the net force
	calculate the total force
	calculate kinetic energy
	calculate potential energy

Solution

In mechanics, multiple forces are often acting on a particular object and, taken together, produce the net force acting on that object. Like force, net force is a vector quantity in that it has magnitude and direction.