ASVAB Mechanical Comprehension Practice Test 521464 Results

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

Review

1 If the handles of a wheelbarrow are 2.5 ft. from the wheel axle and the load is concentrated at a point 0.5 ft. from the axle, how many pounds of load will a 160 lbs. force lift?

47% Answer Correctly

	800
	None of these is correct
	-41.1
	5596.5

Solution

This problem describes a second-class lever and, for a second class lever, the effort force multiplied by the effort distance equals the resistance force multipied by the resistance distance: F_ed_e = F_rd_r. In this problem we're looking for resistance force:
\( F_r = \frac{F_e d_e}{d_r} \)
\( F_r = \frac{160 \times 2.5}{0.5} \)
\( F_r = \frac{400.0}{0.5} \)
\( F_r = 800 \)

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

69% Answer Correctly

	weight
	mass
	potential energy
	density

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.

Which of the following will increase the mechanical advantage of a second-class lever?

55% Answer Correctly

	move the object being lifted closer to the fulcrum
	decrease the length of the lever
	move the object being lifted farther away from the fulcrum
	move the fulcrum between the force and the object being lifted

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.

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

57% Answer Correctly

	driven gear
	idler gear
	driver gear
	input 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.

The science that deals with motion and the forces that produce motion is called which of the following?

57% Answer Correctly

	physics
	engineering
	mechanics
	aeronautics

Solution

Mechanics deals with motion and the forces that produce motion.