ASVAB Mechanical Comprehension Practice Test 996853 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.18
Score	0%	64%

Review

Which class of lever is used to increase force on an object in the same direction as the force is applied?

53% Answer Correctly

	all of these
	first
	second
	third

Solution

A second-class lever is used to increase force on an object in the same direction as the force is applied. This lever requires a smaller force to lift a larger load but the force must be applied over a greater distance. The fulcrum is placed at one end of the lever and mechanical advantage increases as the object being lifted is moved closer to the fulcrum or the length of the lever is increased. An example of a second-class lever is a wheelbarrow.

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

59% Answer Correctly

	efficiency
	mechanical advantage
	power conversion
	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.

Friction between two or more solid objects that are not moving relative to each other is called:

73% Answer Correctly

	dynamic friction
	static friction
	kinetic friction
	gravitational friction

Solution

Static friction is friction between two or more solid objects that are not moving relative to each other. An example is the friction that prevents a box on a sloped surface from sliding farther down the surface.

4 If input effort is 700 ft⋅lb, what output effort will be produced by a machine with a mechanical advantage of 5?

79% Answer Correctly

	140ft⋅lb
	3500 ft⋅lb
	7000ft⋅lb
	0ft⋅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 5 will multiply an input effort of 700 ft⋅lb by 5 to produce an output effort of 3500 ft⋅lb.

What's the first gear in a gear train called?

57% Answer Correctly

	input gear
	driver gear
	driven gear
	idler gear

Solution

A gear train is two or more gears linked together. Gear trains are designed to increase or reduce the speed or torque outpout of a rotating system or change the direction of its output. The first gear in the chain is called the driver and the last gear in the chain the driven gear with the gears between them called idler gears.