SHL Mechanical Comprehension Test - Guide and Practice [2024]

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What Is the SHL Mechanical Comprehension Test?

The SHL Mechanical Comprehension Test is a test conducted by SHL, one of the world's top providers of pre-employment tests. It is designed to assess your ability to understand mechanical concepts and apply them to various situations.

The test contains 18 questions to be answered in 15 minutes.

While the test is somewhat similar to other mechanical aptitude tests, the SHL Mechanical Comprehension Test has several unique features:

• The test is more practical, usually depicting machinery and tools rather than theoretical scenarios.
• All questions have 4 answer options.
• You cannot go back and change a submitted answer.

SHL Mechanical Comprehension Test Topics, Sample Questions, and Answers

While the SHL Mechanical Test covers a variety of topics, there are 5 most common topics. Further below we provide a sample question and answer for each topic.

• Mechanical Devices Interaction
• Gears
• Force and Torque
• Fluid Mechanics
• Tools and Equipment

Let's show one sample question and answer, adapted from actual SHL Mechanical Comprehension Test questions:

Mechanical Devices Interaction

The interaction between various parts of machinery is a common topic in the SHL Mechanical Comprehension Test and is also explicitly mentioned in the test instructions as a major feature of the test.

Questions in this topic will include various mechanical systems, and you will need to predict what happens when they operate.

SHL Mechanical Comprehension Sample Question #1 - Mechanical Devices Interaction

How will each of the horses behave when pushed forward?

A. Both horses will move forward

B. Both horses will move forward, but Horse B will also move up and down.

C. Horse A will move forward, Horse B will move up and down.

D. Both Horses will move forward and up and down.

Correct Answer

Incorrect Answer

While the four large wheels on the base will move both horses forward, Horse B will also move up and down.

Here's why:

The front axis of horse B is not straight (as opposed to horse A) and has an arm in the perpendicular direction. Therefore, it will convert some of the wheel rotation to an up-and-down movement, as depicted in the following diagram (side view):

The arm rotates "inwards," pushing the horse leg up as it goes up (black) and down as it goes down (dashed grey).

Gears

Gears questions are very common in mechanical aptitude tests and the SHL Mechanical Comprehension Test is no exception. You will mostly be asked about things like gear ratio and directionality.

SHL Mechanical Comprehension Sample Question #2 - Gears

In which direction will the grey wheel rotate?

A. Clockwise

B. Counterclockwise

C. It will not rotate

D. Cannot determine

Correct Answer

Incorrect Answer

An intuitive look at the problem can also help see that two rotations are applied on the light cogwheel (marked red) – clockwise from the left and counterclockwise from the right. The light cogwheel is mashed between the two, unable to move (and so is the entire system).

However, this question can also be solved in the traditional way of "counting gears":

Count the gears from the origin to the target (excluding origin):

• A dual number of gears – the same direction.
• An odd number of gears – the opposite direction.

In that case, we can count one gear (the target gear meshes against the origin gear) or two gears, as shown below (red means counterclockwise, blue means clockwise):

Force and Torque

This topic is in and of itself less common in the SHL Mechanical Comprehension Test than in other tests. However, it still includes a variety of fundamental mechanical concepts and understanding it is crucial for succeeding in other topics as well.

This topic includes things like the law of the lever, force equilibrium, etc.

SHL Mechanical Comprehension Sample Question #3 - Force and Torque

Which shelf is less likely to bend?

A. Shelf A

B. Shelf B

C. Both shelves equally

D. It depends on the material the shelves are made of.

Correct Answer

Incorrect Answer

The bending of the shelf is influenced by the load and the distance to the fixed points. That is due to the law of the lever, which states that the longer the arm the load is applied on, the greater force it exerts.

If the load on the shelf is farther from the fixed points, it will exert a large load on the shelf, causing it to bend more.

In that case, although shelf B is longer, the distance between the load and shelf A's fixed points is larger, and therefore it will bend more.

Answer D is incorrect. While the extent to which the shelves will bend does depend on the material they are made of, shelf A will still bend less than shelf B.

Fluid Mechanics

The fluid mechanics topic includes questions on things like hydraulics, flow, and the relationship between heat and pressure.

SHL Mechanical Comprehension Sample Question #4 - Fluid Mechanics

Which liquid is heavier?

A. Liquid A

B. Liquid B

C. Both equally

D. Cannot determine

Correct Answer

Incorrect Answer

Any object floating in a fluid displaces the amount of fluid equal to its weight.

Boat A and B are identical and they both float, therefore we can deduce that they have displaced an equal weight of the fluid.

However, since boat B has displaced a smaller volume of fluid, it means that the fluid is heavier.

Note: Try and think of it intuitively as a wooden boat floating in water and in honey. The boat floating in honey will naturally displace less volume and will float higher in the liquid.

Tools and Equipment

This last topic includes questions that apply physical principles to various power tools and shop equipment. In addition, you will be requested to determine which tools are preferable for specific tasks.

SHL Mechanical Comprehension Sample Question #5 - Tools and Equipment

If both blades have the same engine, which saw will cut faster?

A. Saw A

B. Saw B

C. Both equally, as the cutting speed only depends on the engine.

D. Cannot determine

Correct Answer

Incorrect Answer

Saw A and B are operated by the same engine, and therefore their angular velocity (rounds per minute) is identical.

However, since the blade of saw B is larger than saw A, it will have a larger linear velocity (the distance the blade covers in every rotation).

To illustrate this, look at the following diagram:

When the two wheels rotate at the grey angle, the rim of the outer wheel (red) travels a larger distance than the inner wheel (blue).

Therefore, the larger the circular blade, the more distance it will cover per every round and will cut through the plank faster.

How to Prepare for the SHL Mechanical Reasoning Test?

Preparing for the SHL Mechanical comprehension Test requires a preparation that offers more than a pool of random mechanical questions.

The practical approach of the test and the variety of topics necessitates a practice plan that is comprehensive yet focused. That is achieved by:

• Focusing on the 5 common topics of the SHL Mechanical Reasoning Test.
• Accurately simulating the structure, content, and formatting of the actual SHL Mechanical Comprehension Test.
• Teaching you the physical principles behind questions, so you can apply them to never-seen-before scenarios.

Not sure yet? Take the free SHL practice test.