Mechanical Aptitude Flashcards

Which springs-related statement is FALSE?

Answer: Springs are a kind of simple machines

Springs are not classified as simple machines. Simple machines are basic mechanical devices like levers, pulleys, inclined planes, wheels and axles, wedges, and screws, which change the direction or magnitude of a force. Springs are energy storage devices that deform under load and return to their original shape, converting mechanical energy into potential energy.

What distinguishes a cell from a capacitor most significantly?

Answer: A capacitor builds up charges on its plates, whereas a cell provides the force necessary to make charges flow through the circuit.

A capacitor is a passive electronic component that stores electrical energy in an electric field by accumulating electric charge on two conductive plates separated by a dielectric. A cell (or battery), on the other hand, is an active component that converts chemical energy into electrical energy, providing a continuous electromotive force (voltage) to drive current through a circuit. While both store energy, their mechanisms and primary functions are distinct.

Which assertion concerning air pressure is TRUE?

Answer: Less than 1 atm of air pressure is present 100 kilometers above sea level.

Air pressure decreases significantly with increasing altitude because there is less air above to exert pressure. At sea level, the pressure is approximately 1 atmosphere (atm). At 100 kilometers above sea level, which is well into the Earth's atmosphere but still very high, the air is extremely thin, resulting in a pressure far less than 1 atm.

What is the rate of rotation of the Earth's surface, expressed in kilometers per hour? The Earth has a 6370 km radius. Assign a whole number as the answer.

Answer: 1667 km/h

To calculate the speed of rotation at the Earth's equator, we find the circumference (2 * pi * radius) and divide it by the time for one rotation (24 hours). With a radius of 6370 km, the circumference is approximately 40023.8 km. Dividing this by 24 hours gives approximately 1667.66 km/h, which rounds to 1667 km/h.

What value stays the same throughout a ballistic trajectory?

Answer: Acceleration

In a ballistic trajectory, assuming negligible air resistance, the only significant force acting on the object is gravity. Therefore, the acceleration remains constant throughout the trajectory, equal to the acceleration due to gravity (approximately 9.8 m/s² downwards). Velocity changes continuously in both magnitude and direction, and distance is constantly increasing.

Although the connection that sends current to the iron is chilly, an electric iron heats up. As a result of:

Answer: Electric iron converts electricity into heat

An electric iron heats up because it contains a heating element, typically a high-resistance wire, which converts electrical energy into thermal energy (heat) due to the Joule heating effect. The connecting cables, however, are designed to have very low resistance, minimizing energy loss as heat and thus remaining relatively cool while efficiently delivering current to the iron.

Which one of the following DOES NOT operate via magnetism?

Answer: Vehicle

While some components within a vehicle (like the starter motor or alternator) utilize magnetism, a vehicle as a whole does not primarily operate via magnetism for its main function of propulsion. Its movement typically relies on internal combustion engines or electric motors that convert fuel or electrical energy into mechanical motion. NMR apparatus and compasses, however, are fundamentally based on magnetic principles.

Used when dealing with bricks or concrete blocks to distribute, shape, and smooth mortar.

Answer: Masons Trowel (Brick Trowel)

A mason's trowel, specifically a brick trowel, is a hand tool with a flat, triangular metal blade and a handle, designed for spreading, shaping, and smoothing mortar or concrete. It is essential for laying bricks, blocks, and stones, allowing masons to precisely apply and level the bonding material between them.

An adjusting wrench for tightening or loosening nuts and bolts of various sizes.

Answer: Crescent Wrench

A Crescent wrench, also known as an adjustable wrench, features a movable jaw that can be adjusted to fit various sizes of nuts and bolts. This versatility makes it a common and useful tool for tasks where specific fixed-size wrenches are not available or when dealing with different fastener dimensions.

Used when using a tap to cut internal screw threads. It makes it possible to apply pressure with a better and more even grip.

Answer: Tap Wrench

A tap wrench is a specialized hand tool designed to hold and turn a tap, which is used to cut internal screw threads into a pre-drilled hole. Its handles provide leverage and a stable, even grip, allowing the user to apply consistent pressure and rotation for accurate thread cutting.

Used in a power drill to create large holes in plastic or wood.

Answer: Spade Bit (Flat Bit)

A spade bit, also known as a flat bit, is a type of drill bit with a flat, paddle-shaped head and a pointed tip. It is specifically designed for quickly drilling large diameter holes in wood, plastic, and other soft materials when used with a power drill.

Used largely in the same way as a brace, with the speed and flexibility of employing different accessories and bits being the difference.

Answer: Power Drill

A power drill serves a similar function to a brace (a hand-powered drilling tool) but offers significantly increased speed and versatility. It can rapidly rotate various drill bits and accessories, making it efficient for drilling holes, driving screws, and performing other tasks in a wide range of materials.

Primarily used to cut fine joints in wood, as in a tenon, lap, or dovetail. It can also be used in conjunction with a miter box to cut accurate 45- or 90-degree angles.

Answer: Back Saw (Tenon Saw)

A back saw, often called a tenon saw, is characterized by its stiffening rib (the 'back') along the top edge of the blade, which ensures precise, straight cuts. Its fine teeth and rigid blade make it ideal for cutting accurate joinery like tenons, laps, and dovetails, and it's commonly used with a miter box for angled cuts.

A tool for plotting or drawing angles (0 to 180 degrees) on a surface.

Answer: Protractor

A protractor is a common geometric tool used for measuring and drawing angles. It typically has a semicircular or circular shape with degree markings from 0 to 180 (or 360) degrees, allowing for precise angular measurements and constructions on various surfaces.

Used to establish the depths of grooves, mortises, and holes.

Answer: Depth Gauge

A depth gauge is a precision measuring instrument specifically designed to accurately determine the depth of holes, slots, grooves, and steps. It typically consists of a measuring rod that extends from a reference surface, providing precise readings for various machining and woodworking applications.

Used in various related light electrical jobs as well as to solder wire to create contact terminals.

Answer: Soldering Gun

A soldering gun is a handheld tool used for soldering, which involves melting solder to join metal workpieces, typically wires or electronic components. It quickly heats up to high temperatures, making it suitable for light electrical work, repairing circuits, and creating strong electrical connections.