How to Prepare for the Mechanical Aptitude Test

Mechanical Reasoning The Mechanical Reasoning portion of the SRA measures your ability to understand basic mechanical principles of machinery, tools, and motion. There are commercially available study guides for this portion of the SRA which include: Barron’s, Mechanical Aptitude and Spatial Relations, 3rd edition, by Joel Weisen. For further study. Ou should look for a test preparation study book in the school or public library for preparing for Mechanical Reasoning, also called Mechanical Aptitude, tests. This subject is sometimes included as part of a larger test study kit for IQ or vocational aptitude testing, such as DAT (Differential Aptitude Testing).

The most tried and true method for preparing for this and any other test will be to practise beforehand. Knowing what to expect and how to answer the questions you will encounter will give you a major advantage over other candidates.

Our free mechanical aptitude sample test can give you a baseline for the concepts and skill level required to pass your mechanical reasoning test. Want more in-depth mechanical aptitude test practice? Our full mechanical reasoning PrepPacks™ include dozens of practice questions, complete study guides, answer explanations and more to ensure that you are fully prepared come test day.

Mechanical Reasoning Test Questions and Answers

The purpose of a mechanical reasoning test is to evaluate your understanding and application of mechanical concepts to find solutions to a variety of mechanical scenarios. Questions that you will often encounter on a mechanical aptitude test include:

Acceleration	Applied maths	Balancing scales
Ballistics	Circular motion	Clamps
Cogs	Friction	Gears
Gravity	Kinetic and potential energy	Levers
Magnetism	Mechanical terminology	Mirrors and reflection
Pressure and weights	Pulleys	Screws
Shafts	Simple electrical circuits	Spatial or visual relations
Springs	Tools of the trade	Volumes
Wheels and belts	-	-

Due to the wide range of topics covered by mechanical reasoning tests, it is no wonder that practising beforehand is crucial to a successful result. Through in-depth practice tests and study guides, our mechanical aptitude PrepPacks™ are designed to help you improve your knowledge and application of mechanical and electrical concepts, thus giving you the ability to pass your pre-employment exams with ease.

Gears & Pulleys

A gear can be represented as either a wheel or cylinder. A major characteristic of these wheels/ cylinders are the cogs/ teeth running along their outside edges. The three main purposes of gears are to change the direction of motion, increase or reduce speed and force, or to transmit force.

Questions regarding gears will typically use the rules below to solve. The fundamental rules of thumb for solving mechanical reasoning questions concerning gears/ cogwheels are:

If gears are connected (meshed), adjacent gears will move in the opposite direction. If there are an odd number of cogwheels, the last wheel will turn in the same direction as the first wheel. In a system with an even number of cogwheels, the last cogwheel will turn in the opposite direction of the first.

Free Mechanical Reasoning Study Guide

Consider the following example:

Unmeshed (not physically touching) gears that are connected by a chain or belt will move in the same direction. If the chain is crossed,they will move in opposite directions:
- There is a trade-off between force and speed: more teeth – lower speed, more force.
- Less teeth – higher speed, less force.
Gear ratio: N1/N2 = V2/V1 (N is the number of teeth on gear 1/2, V is the rotation velocity).

For more information regarding the types of questions on gears that you may encounter on your assessment, please see below:

When a belt or a chain connects to unmeshed cogwheels, both wheels will turn in the same direction. If the belt is crossed, they will turn in opposite directions.

In this case, the wheel’s velocity will be proportional to its radius rather than its number of teeth; aka its gear ratio:

larger wheels will turn more slowly than smaller wheels. A larger wheel has a greater circumference and therefore covers a greater distance for every single turn, whereas a smaller wheel has to turn more than once in order to cover the same distance. The ratio of their diameters (or equivalently, the ratio of their radii) is directly proportional to the gear ratio and is inversely proportional to the ratio of wheel velocities.

When an internal cogwheel (light blue) and an external cogwheel (grey) are joined together, they will move in the same direction. However, the velocity-to-size ratio will remain as with internal cogwheels.

When a cogwheel connected to a toothed rack, the force is transferred from circular to linear. In this instance, the rack will move in the same direction as the wheel at the meshing point. The illustration above shows the cogwheel moving in a clockwise direction. At the meshing point, you can see that the wheel's direction is moving toward the left (red arrow). Because of the rack underneath will move to the left.

In general:

Pulleys

Pulley systems typically involve one or more wheels controlled by a cord/ rope/ belt. By changing the direction of force applied to the rope, pulleys can be used to lift heavy objects/ weights. There are a variety of different pulley systems that you will encounter during a mechanical aptitude assessment. These include:

In a fixed pulley system, the load will move while the pulley does not. The pulley does not reduce the force needed to lift the load, it merely changes its direction.

In a moveable pulley system, the pulley will move along with the load. This, in turn, cuts the force of lifting the object and its weight in half.

As with gears, here there is also a trade-off. You will need half the force to lift the load, but double the amount of rope. E.g. to lift a load with a moveable pulley to a height of 1 meter, you will need 2 meters of rope. That rate increases as the number of pulleys increases.

These systems include more than one pulley and will either include both fixed and/ or moveable pulleys. In these systems, the force for lifting an object will be reduced but the distance for doing so will increase. The force required to lift the object is equal to the number of ropes supporting it.

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Important Formulas

It is wise to brush up on certain mechanical formulas when preparing for a mechanical aptitude test. Below are some examples of formulas that you should know prior to sitting a mechanical reasoning test:

W = Width

Circle

Area = πr2

R = Radius

Triangle

Area = ½bh Gts fc-515ls ethernet driver download.

B = Base

H = Height

Cuboid

V = b x h x w

Free Mechanical Reasoning Study Guide

Cylinder

V = πr2 x h

B = Base

H = Height

W = Width

R = Radius

Weight (W) x Distance (D1) = Force (F) x Distance (D2)

W = Weight

D1 = Distance from fulcrum to weight

F= Force required

D2= Distance from fulcrum to force point

N1/N2 = V2/V1

N1 x V1 = N2 x V2

N1 = Number of teeth on wheel 1

Mechanical Reasoning Free Study Guide

N2 = Number of teeth on wheel 2

V1 = Velocity of wheel 1

V2 = Velocity of wheel 2

So if N1 = 8, N2 = 5. The gear ratio (1-2) will be = N1/N2 = V2/V1 = 8/5.

PV = nRT

P = Pressure

V = Volume

n = number of gas particles (amount of gas)

R = Gas constant (just a number)

T = Temperature

It should be noted that it is not as important to remember the formula exactly as it is important to know what it must hold. I