Mechanical Aptitude Pre-Employment Quiz: Are You Technically Skilled?

An adjustable wrench fits hexagonal bolt heads and can be resized to match different bolt sizes, making it the ideal tool in this scenario. A hammer is for impact, not turning bolts. A pipe cutter is designed for cutting pipes, and a flathead screwdriver doesn’t grip a hexagon properly. Using the wrong tool can strip or damage the bolt, whereas a wrench applies even torque and preserves the integrity of both tool and bolt.

A pulley system reduces the force needed to lift a load by distributing the weight across multiple supporting segments of rope. This doesn’t reduce the work done (energy remains conserved), but it makes lifting feel easier by lowering the force required. The more pulleys added, the less input force needed. Gravity is still at play, but it’s the mechanical advantage that does the trick here—not the elimination of weight.

Oil is used between moving parts to reduce friction by creating a slippery film that separates contact surfaces. This minimizes heat generation and wear. If friction increases instead, parts may overheat and degrade faster. Adding weight or absorbing heat isn’t oil’s core function—its main benefit is lubrication. Regular maintenance and proper oiling are essential for machinery longevity and smooth functioning.

Torque measures the turning or rotational force applied around an axis. It's calculated as the product of force and the distance from the pivot point (Torque = Force × Distance). It determines how much rotational push is being exerted. Speed measures how fast something moves, linear momentum applies to straight-line motion, and electrical current is unrelated to mechanical rotation. Torque is fundamental in engine design and mechanical leverage.

A long wrench provides a longer lever arm, increasing the torque applied with the same amount of force. This makes it easier to overcome the resistance of a tight or rusted bolt. The principle is based on the torque equation—longer handle, greater torque. It’s not about comfort or tool weight, but about mechanical leverage. This principle is vital in tool design for mechanics and engineers alike.

When a gear with 20 teeth drives a gear with 10 teeth, the smaller gear spins faster—twice as fast, to be precise. This is due to gear ratio mechanics. The ratio of 20:10 equals 2:1, meaning the driven gear (10 teeth) must complete two rotations for every one of the driver gear. This increases speed but reduces torque in the driven gear. Understanding gear ratios is crucial for optimizing speed and force in mechanical systems.

Inertia is the tendency of an object to resist a change in its motion. When you stop pedaling a bike, it keeps moving due to inertia until friction (from air resistance and contact with the ground) slows it down. Gravity affects vertical motion, and centripetal force keeps the bike in curved motion, but inertia alone explains why the forward motion continues without additional force. This principle is part of Newton’s First Law of Motion.

Copper expands the most among the listed materials when heated due to its high thermal expansion coefficient. This property is important in systems where metals are exposed to varying temperatures, like in pipelines or engines. Glass and wood have lower expansion rates and may crack instead of expanding smoothly. Plastic varies depending on the type, but copper is widely used where thermal conductivity and expansion are key.

A screw is an inclined plane wrapped around a cylinder, making it ideal for converting rotational motion into linear force. This helps it hold materials together tightly or lift loads gradually. A wedge splits objects apart, and a lever provides pivoting force. A wheel and axle rotates around a central shaft. While all are simple machines, the inclined plane is the best description of a screw’s mechanical function.

In a system with two meshing gears (cogs), when one turns clockwise, the other turns counterclockwise. This is because the teeth of one gear push against the other in the opposite direction. This reversal of rotation is essential in mechanical systems where direction of force needs to be controlled. If the gears were on the same shaft, they’d rotate in the same direction, but meshing gears always rotate oppositely.