ASVAB Mechanical Comprehension Practice Test 69665 Results

	Your Results	Global Average
Questions	5	5
Correct	0	2.91
Score	0%	58%

Review

A screw is most like which of the following other simple machines?

50% Answer Correctly

	inclined plane
	wheel and axle
	block and tackle
	first-class lever

Solution

A screw is an inclined plane wrapped in ridges (threads) around a cylinder. The distance between these ridges defines the pitch of the screw and this distance is how far the screw advances when it is turned once. The mechanical advantage of a screw is its circumference divided by the pitch.

2 If you lift a 11 lbs. rock 50 ft. from the ground, how much work have you done?

71% Answer Correctly

	0 ft⋅lb
	61 ft⋅lb
	-39 ft⋅lb
	550 ft⋅lb

Solution

Work is force times distance. In this case, the force is the weight of the rock so:
\( W = F \times d \)
\( W = 11 \times 50 \)
\( W = 550 \)

Force of friction due to kinetic friction is __________ the force of friction due to static friction.

40% Answer Correctly

	higher than
	lower than
	the same as
	opposite

Solution

The formula for force of friction (F_f) is the same whether kinetic or static friction applies: F_{f =}μF_N. To distinguish between kinetic and static friction, μ_k and μ_s are often used in place of μ.

What type of load is sudden and for a relatively short duration?

70% Answer Correctly

	concentrated load
	impact load
	non-uniformly distributed load
	dynamic load

Solution

A concentrated load acts on a relatively small area of a structure, a static uniformly distributed load doesn't create specific stress points or vary with time, a dynamic load varies with time or affects a structure that experiences a high degree of movement, an impact load is sudden and for a relatively short duration and a non-uniformly distributed load creates different stresses at different locations on a structure.

Which of the following is the formula for gravitational potential energy?

62% Answer Correctly

	\(PE = { 1 \over 2} mg^2\)
	\(PE = mgh\)
	\(PE = { 1 \over 2} mv^2\)
	\(PE = mg^2h\)

Solution

Gravitational potential energy is energy by virtue of gravity. The higher an object is raised above a surface the greater the distance it must fall to reach that surface and the more velocity it will build as it falls. For gravitational potential energy, PE = mgh where m is mass (kilograms), h is height (meters), and g is acceleration due to gravity which is a constant (9.8 m/s²).