ASVAB Mechanical Comprehension Practice Test 965850 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.20
Score	0%	64%

Review

Two or more pulleys used together are called:

71% Answer Correctly

	third-class lever
	block and tackle
	wheel and axle
	gears

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.

Drag is a type of:

82% Answer Correctly

	potential energy
	work
	friction
	kinetic energy

Solution

Drag is friction that opposes movement through a fluid like liquid or air. The amount of drag depends on the shape and speed of the object with slower objects experiencing less drag than faster objects and more aerodynamic objects experiencing less drag than those with a large leading surface area.

When it comes to force, mass and acceleration have what kind of relationship?

66% Answer Correctly

	inverse
	exponential
	linear
	logarithmic

Solution

Newton's Second Law of Motion states that "The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object." This Law describes the linear relationship between mass and acceleration when it comes to force and leads to the formula F = ma or force equals mass multiplied by rate of acceleration.

4 What is the power output of a 5 hp engine that's 25% efficient?

40% Answer Correctly

	0 \( \frac{ft⋅lb}{s} \)
	125 \( \frac{ft⋅lb}{s} \)
	687.5 \( \frac{ft⋅lb}{s} \)
	1375 \( \frac{ft⋅lb}{s} \)

Solution

\( Efficiency = \frac{Power_{out}}{Power_{in}} \times 100 \)
Solving for power out: \( P_{o} = \frac{E \times P_{i}}{100} \)
Knowing that 1 hp = 550 \( \frac{ft⋅lb}{s} \), P_i becomes 5 hp x 550 \( \frac{ft⋅lb}{s} \) = 2750 \( \frac{ft⋅lb}{s} \)
\( P_{o} = \frac{E \times P_{i}}{100} = \frac{25 \times 2750 \frac{ft⋅lb}{s}}{100} \) \( = \frac{68750 \frac{ft⋅lb}{s}}{100} \) = 687.5 \( \frac{ft⋅lb}{s} \)

A box is resting on a smooth floor. Static friction is present:

59% Answer Correctly

	only if normal force is present
	at all times
	if the coefficient of friction is greater than one
	when an attempt is made to move the box

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).