ASVAB Mechanical Comprehension Practice Test 512195 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.26
Score	0%	65%

Review

1 If input effort is 600 ft⋅lb, what output effort will be produced by a machine with a mechanical advantage of 8?

79% Answer Correctly

	9600ft⋅lb
	75ft⋅lb
	2400ft⋅lb
	4800 ft⋅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 600 ft⋅lb by 8 to produce an output effort of 4800 ft⋅lb.

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

53% Answer Correctly

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

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.

The force exerted on an object due to gravity is called:

70% Answer Correctly

	mass
	density
	weight
	potential energy

Solution

Mass is an intrinsic property of matter and does not vary. Weight is the force exerted on the mass of an object due to gravity and a specific case of Newton's Second Law of Motion. Replace force with weight and acceleration with acceleration due to gravity on Earth (g) and the result is the formula for weight: W = mg or, substituting for g, weight equals mass multiplied by 9.8 m/s².

The mechanical advantage of a block and tackle is equal to which of the following?

69% Answer Correctly

	the number of pulleys
	the number of loads
	the number of connecting ropes
	the number of input forces

Solution

Two or more pulleys used together constitute a block and tackle which, unlike a fixed pulley, does impart mechanical advantage as a function of the number of pulleys that make up the arrangement. So, for example, a block and tackle with three pulleys would have a mechanical advantage of three.

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

54% Answer Correctly

	lower than
	higher than
	equal to
	opposite

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).