A 10-pound weight is placed 6 feet from the fulcrum of a lever. To balance it, how far from the fulcrum must a 15-pound weight be placed on the opposite side?

Correct answer: 4 feet. Lever balance requires equal torques on both sides of the fulcrum: W1 x D1 = W2 x D2. Plug in: 10 lb x 6 ft = 15 lb x D2, so 60 = 15 x D2, and D2 = 4 feet. Choice A (2 feet) divides 6 by 3 instead of using the torque equation. Choice C (6 feet) keeps the same distance and ignores that the heavier weight needs a shorter arm. Choice D (9 feet) puts the heavier weight farther out, which would unbalance the lever further since 15 lb x 9 ft = 135 lb-ft, more than double the 60 lb-ft on the other side.

If a small gear with 10 teeth meshes with a large gear with 40 teeth, and the small gear rotates at 200 RPM, how fast does the large gear rotate?

Correct answer: 50 RPM. Meshing gears conserve linear tooth speed, so RPM is inversely proportional to tooth count: RPM_large = RPM_small x (teeth_small / teeth_large) = 200 x (10/40) = 50 RPM. Choice A (25 RPM) divides by 8 instead of 4, doubling the reduction. Choice C (100 RPM) only halves the speed, applying a 2:1 ratio instead of the actual 4:1. Choice D (800 RPM) inverts the formula and multiplies 200 by 4, treating the large gear as the faster one when in fact the larger gear always turns slower than the smaller one it meshes with.

A 200-pound crate is resting on a flat surface. If you push it horizontally with a force of 50 pounds and it does not move, what is the force of friction acting on the crate?

Correct answer: 50 pounds. Newton's Second Law: if an object does not accelerate, the net force is zero. The crate is stationary, so static friction adjusts to exactly cancel the applied push. Friction = 50 pounds, opposite to the push. Choice A (0 pounds) ignores that something must be canceling the 50-pound push. Choice C (150 pounds) confuses friction with the difference between weight and applied force. Choice D (200 pounds) uses the full weight as the friction force, but weight acts vertically and is canceled by the normal force, not by horizontal friction. Static friction only equals what is needed to prevent motion, up to its maximum.

A wheel and axle system has a wheel with a radius of 12 inches and an axle with a radius of 3 inches. What is the mechanical advantage of this system?

Correct answer: 4. Mechanical advantage of a wheel-and-axle equals the wheel radius divided by the axle radius: MA = 12 / 3 = 4. The effort applied at the wheel's rim travels a larger circle, while the axle moves a smaller circle with greater force. Choice A (2) halves the correct ratio, possibly confusing radius with diameter on only one side. Choice B (3) uses the axle radius alone as the answer. Choice D (6) appears to add the radii (12 + 3) and halve them, or otherwise mix dimensions. Only the radius ratio gives the correct mechanical advantage.

A fixed pulley changes the direction of force but does NOT change the amount of force required. Which statement about a fixed pulley is correct?

Correct answer: It redirects the force without any mechanical advantage.. A fixed pulley has only one rope segment supporting the load, so its mechanical advantage equals 1. Its only function is to change the direction of the applied force, not its magnitude. Choice A (reduces force by half) describes a single movable pulley, which has MA = 2. Choice B (multiplies by rope segments) describes a block-and-tackle with multiple supporting strands. Choice D (eliminates gravity) is physically impossible; pulleys redistribute or redirect force but never cancel weight. Only choice C correctly identifies that the load still requires a pulling force equal to its weight.

It reduces the force needed by half.

It multiplies the force by the number of rope segments.

It eliminates the effect of gravity on the load.

Which of the following changes would increase the pressure exerted by a block resting on a table?

Correct answer: Placing the block on a smaller face so less area contacts the table. Pressure equals force divided by contact area: P = F / A. With weight held constant, shrinking the area concentrates the same force onto fewer square inches and raises pressure. Choice A (tilting at 45 degrees) actually reduces the normal force on the table because part of the weight vector shifts off-axis, lowering pressure. Choice B (increasing surface area) spreads force over more area and decreases pressure, the opposite of what is asked. Choice D (moving the block) changes location only; both area and weight stay the same, so pressure is unchanged. Only reducing the contact face increases pressure.

Tilting the block at a 45-degree angle

Increasing the surface area in contact with the table

Moving the block to the center of the table

If a hydraulic jack applies 10 pounds of force over a piston with an area of 2 square inches, what is the pressure transmitted through the hydraulic fluid?

Correct answer: 5 psi. Pressure equals force divided by area: P = F / A = 10 lb / 2 in^2 = 5 psi. Pascal's principle states this pressure is transmitted equally to every part of the enclosed fluid. Choice A (2 psi) uses the area as the answer directly, ignoring the force. Choice C (12 psi) adds the force and area (10 + 2), which mixes incompatible units. Choice D (20 psi) multiplies force by area (10 x 2), inverting the formula. The pressure-versus-force distinction matters: pressure is what the fluid carries; force is what each piston exerts, and the two are connected by piston area.

A ball rolls off a horizontal table and follows a curved path to the ground. This curved path is an example of which type of motion?

Correct answer: Projectile motion. Projectile motion describes any object launched with a horizontal velocity that is then acted on only by gravity. The horizontal speed stays constant while vertical speed grows under g, producing a parabolic path. Choice A (circular motion) requires a centripetal force pulling toward a center point, not a constant downward gravitational pull. Choice B (simple harmonic motion) describes oscillation about an equilibrium, like a pendulum or spring, not a one-way arc. Choice D (linear motion) requires a straight-line path, but the ball curves downward as it leaves the table, ruling out a straight trajectory.

In an inclined plane, increasing the length of the ramp while keeping the height constant will:

Correct answer: Increase the mechanical advantage by reducing effort force. Mechanical advantage of an inclined plane equals ramp length divided by ramp height: MA = L / h. Increasing L while keeping h fixed makes the ratio larger, so MA goes up and the required effort force goes down. Choice A (increase effort) reverses the trade-off; a longer ramp lowers effort, not raises it. Choice B (decrease MA) inverts the formula. Choice D (no effect) ignores that MA depends explicitly on the L/h ratio. Work in equals work out: a longer ramp spreads the same lifting work over more distance, so the force at each point drops.

Increase the effort force needed to move the load

Decrease the mechanical advantage

Have no effect on mechanical advantage

How many free Mechanical Comprehension practice questions are here?

This page has 9 free ASVAB Mechanical Comprehension questions, each with the correct answer and a full worked explanation. They're free to use with no account required.

Does Mechanical Comprehension count toward my AFQT score?

No. Mechanical Comprehension is not one of the four AFQT subtests, so it does not affect your AFQT/enlistment score. It does feed line scores that determine which military jobs you qualify for.

What does the Mechanical Comprehension subtest cover?

Tests understanding of physical principles and simple machines. Think levers, pulleys, gears, and basic physics applied to real situations. On the CAT-ASVAB it has 15 questions with about 20 minutes to answer them. Topics include: Simple machines, force, motion, pressure, mechanical advantage.

Are these the same as the real ASVAB questions?

No. These are original practice questions calibrated to match the style and difficulty of the real ASVAB. The actual test is a secure exam, so no one publishes its live items. Practicing this format is the closest legitimate prep.

Free ASVAB Mechanical Comprehension Practice Test

9 Mechanical Comprehension (MC) practice questions, each with a worked explanation of the right answer.

Last updated May 2026

The ASVAB Mechanical Comprehension (MC) subtest covers simple machines, force, motion, pressure, mechanical advantage. On the computer-adaptive CAT-ASVAB it has 15 questions with about 20 minutes to answer. It is not an AFQT subtest, but it feeds the line scores that decide which jobs you qualify for. Work the 9 questions below, then read each explanation. Understanding why the answer is right is what raises your score.

Question 1· Mechanical Comprehension
A 10-pound weight is placed 6 feet from the fulcrum of a lever. To balance it, how far from the fulcrum must a 15-pound weight be placed on the opposite side?
- A.2 feet
- B.4 feet
- C.6 feet
- D.9 feet
Show answer & explanationHide answer
Correct answer: B. 4 feet
Why: Lever balance requires equal torques on both sides of the fulcrum: W1 x D1 = W2 x D2. Plug in: 10 lb x 6 ft = 15 lb x D2, so 60 = 15 x D2, and D2 = 4 feet. Choice A (2 feet) divides 6 by 3 instead of using the torque equation. Choice C (6 feet) keeps the same distance and ignores that the heavier weight needs a shorter arm. Choice D (9 feet) puts the heavier weight farther out, which would unbalance the lever further since 15 lb x 9 ft = 135 lb-ft, more than double the 60 lb-ft on the other side.
Question 2· Mechanical Comprehension
If a small gear with 10 teeth meshes with a large gear with 40 teeth, and the small gear rotates at 200 RPM, how fast does the large gear rotate?
- A.25 RPM
- B.50 RPM
- C.100 RPM
- D.800 RPM
Show answer & explanationHide answer
Correct answer: B. 50 RPM
Why: Meshing gears conserve linear tooth speed, so RPM is inversely proportional to tooth count: RPM_large = RPM_small x (teeth_small / teeth_large) = 200 x (10/40) = 50 RPM. Choice A (25 RPM) divides by 8 instead of 4, doubling the reduction. Choice C (100 RPM) only halves the speed, applying a 2:1 ratio instead of the actual 4:1. Choice D (800 RPM) inverts the formula and multiplies 200 by 4, treating the large gear as the faster one when in fact the larger gear always turns slower than the smaller one it meshes with.
Question 3· Mechanical Comprehension
A 200-pound crate is resting on a flat surface. If you push it horizontally with a force of 50 pounds and it does not move, what is the force of friction acting on the crate?
- A.0 pounds
- B.50 pounds
- C.150 pounds
- D.200 pounds
Show answer & explanationHide answer
Correct answer: B. 50 pounds
Why: Newton's Second Law: if an object does not accelerate, the net force is zero. The crate is stationary, so static friction adjusts to exactly cancel the applied push. Friction = 50 pounds, opposite to the push. Choice A (0 pounds) ignores that something must be canceling the 50-pound push. Choice C (150 pounds) confuses friction with the difference between weight and applied force. Choice D (200 pounds) uses the full weight as the friction force, but weight acts vertically and is canceled by the normal force, not by horizontal friction. Static friction only equals what is needed to prevent motion, up to its maximum.
Question 4· Mechanical Comprehension
A wheel and axle system has a wheel with a radius of 12 inches and an axle with a radius of 3 inches. What is the mechanical advantage of this system?
- A.2
- B.3
- C.4
- D.6
Show answer & explanationHide answer
Correct answer: C. 4
Why: Mechanical advantage of a wheel-and-axle equals the wheel radius divided by the axle radius: MA = 12 / 3 = 4. The effort applied at the wheel's rim travels a larger circle, while the axle moves a smaller circle with greater force. Choice A (2) halves the correct ratio, possibly confusing radius with diameter on only one side. Choice B (3) uses the axle radius alone as the answer. Choice D (6) appears to add the radii (12 + 3) and halve them, or otherwise mix dimensions. Only the radius ratio gives the correct mechanical advantage.
Question 5· Mechanical Comprehension
A fixed pulley changes the direction of force but does NOT change the amount of force required. Which statement about a fixed pulley is correct?
- A.It reduces the force needed by half.
- B.It multiplies the force by the number of rope segments.
- C.It redirects the force without any mechanical advantage.
- D.It eliminates the effect of gravity on the load.
Show answer & explanationHide answer
Correct answer: C. It redirects the force without any mechanical advantage.
Why: A fixed pulley has only one rope segment supporting the load, so its mechanical advantage equals 1. Its only function is to change the direction of the applied force, not its magnitude. Choice A (reduces force by half) describes a single movable pulley, which has MA = 2. Choice B (multiplies by rope segments) describes a block-and-tackle with multiple supporting strands. Choice D (eliminates gravity) is physically impossible; pulleys redistribute or redirect force but never cancel weight. Only choice C correctly identifies that the load still requires a pulling force equal to its weight.
Question 6· Mechanical Comprehension
Which of the following changes would increase the pressure exerted by a block resting on a table?
- A.Tilting the block at a 45-degree angle
- B.Increasing the surface area in contact with the table
- C.Placing the block on a smaller face so less area contacts the table
- D.Moving the block to the center of the table
Show answer & explanationHide answer
Correct answer: C. Placing the block on a smaller face so less area contacts the table
Why: Pressure equals force divided by contact area: P = F / A. With weight held constant, shrinking the area concentrates the same force onto fewer square inches and raises pressure. Choice A (tilting at 45 degrees) actually reduces the normal force on the table because part of the weight vector shifts off-axis, lowering pressure. Choice B (increasing surface area) spreads force over more area and decreases pressure, the opposite of what is asked. Choice D (moving the block) changes location only; both area and weight stay the same, so pressure is unchanged. Only reducing the contact face increases pressure.
Question 7· Mechanical Comprehension
If a hydraulic jack applies 10 pounds of force over a piston with an area of 2 square inches, what is the pressure transmitted through the hydraulic fluid?
- A.2 psi
- B.5 psi
- C.12 psi
- D.20 psi
Show answer & explanationHide answer
Correct answer: B. 5 psi
Why: Pressure equals force divided by area: P = F / A = 10 lb / 2 in^2 = 5 psi. Pascal's principle states this pressure is transmitted equally to every part of the enclosed fluid. Choice A (2 psi) uses the area as the answer directly, ignoring the force. Choice C (12 psi) adds the force and area (10 + 2), which mixes incompatible units. Choice D (20 psi) multiplies force by area (10 x 2), inverting the formula. The pressure-versus-force distinction matters: pressure is what the fluid carries; force is what each piston exerts, and the two are connected by piston area.
Question 8· Mechanical Comprehension
A ball rolls off a horizontal table and follows a curved path to the ground. This curved path is an example of which type of motion?
- A.Circular motion
- B.Simple harmonic motion
- C.Projectile motion
- D.Linear motion
Show answer & explanationHide answer
Correct answer: C. Projectile motion
Why: Projectile motion describes any object launched with a horizontal velocity that is then acted on only by gravity. The horizontal speed stays constant while vertical speed grows under g, producing a parabolic path. Choice A (circular motion) requires a centripetal force pulling toward a center point, not a constant downward gravitational pull. Choice B (simple harmonic motion) describes oscillation about an equilibrium, like a pendulum or spring, not a one-way arc. Choice D (linear motion) requires a straight-line path, but the ball curves downward as it leaves the table, ruling out a straight trajectory.
Question 9· Mechanical Comprehension
In an inclined plane, increasing the length of the ramp while keeping the height constant will:
- A.Increase the effort force needed to move the load
- B.Decrease the mechanical advantage
- C.Increase the mechanical advantage by reducing effort force
- D.Have no effect on mechanical advantage
Show answer & explanationHide answer
Correct answer: C. Increase the mechanical advantage by reducing effort force
Why: Mechanical advantage of an inclined plane equals ramp length divided by ramp height: MA = L / h. Increasing L while keeping h fixed makes the ratio larger, so MA goes up and the required effort force goes down. Choice A (increase effort) reverses the trade-off; a longer ramp lowers effort, not raises it. Choice B (decrease MA) inverts the formula. Choice D (no effect) ignores that MA depends explicitly on the L/h ratio. Work in equals work out: a longer ramp spreads the same lifting work over more distance, so the force at each point drops.

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What's on the ASVAB Mechanical Comprehension subtest

Tests understanding of physical principles and simple machines. Think levers, pulleys, gears, and basic physics applied to real situations.

Common topics you'll see:

Levers & fulcrums
Pulleys & mechanical advantage
Gears & gear ratios
Force, work & energy
Pressure & hydraulics
Properties of materials
Structural support & load distribution
Fluid dynamics basics
Thermodynamics basics

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FAQ

How many free Mechanical Comprehension practice questions are here?: This page has 9 free ASVAB Mechanical Comprehension questions, each with the correct answer and a full worked explanation. They're free to use with no account required.
Does Mechanical Comprehension count toward my AFQT score?: No. Mechanical Comprehension is not one of the four AFQT subtests, so it does not affect your AFQT/enlistment score. It does feed line scores that determine which military jobs you qualify for.
What does the Mechanical Comprehension subtest cover?: Tests understanding of physical principles and simple machines. Think levers, pulleys, gears, and basic physics applied to real situations. On the CAT-ASVAB it has 15 questions with about 20 minutes to answer them. Topics include: Simple machines, force, motion, pressure, mechanical advantage.
Are these the same as the real ASVAB questions?: No. These are original practice questions calibrated to match the style and difficulty of the real ASVAB. The actual test is a secure exam, so no one publishes its live items. Practicing this format is the closest legitimate prep.

Free practice tests for the other subtests

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