EIAT Mechanical Flashcards

A gear with 40 teeth meshes with a gear with 10 teeth. If the smaller gear rotates at 200 RPM, what is the speed of the larger gear?

Answer: 50 RPM

Gear ratio = 10/40 = 1/4, so the larger gear turns at 200 × (10/40) = 50 RPM.

Which type of pulley system provides a mechanical advantage of 3?

Answer: A block and tackle with 3 rope segments supporting the load

Mechanical advantage in a block-and-tackle equals the number of rope segments supporting the moving block.

A wrench applies 50 lb of force at 12 inches from the bolt center. What is the torque applied?

Answer: 600 lb-in

Torque = Force × Distance = 50 lb × 12 in = 600 lb-in.

An inclined plane is 10 feet long and rises 2 feet. A 500 lb crate is pushed up the ramp. Approximately how much force is required (ignoring friction)?

Answer: 100 lb

Mechanical advantage = length/height = 10/2 = 5, so force = 500/5 = 100 lb.

Two gears rotate in the same direction when:

Answer: An even number of gears links them in a gear train

Each meshing pair reverses direction; an even number of intermediate gears results in the output rotating the same direction as the input.

Which simple machine is essentially a circular lever?

Answer: Wheel and axle

A wheel and axle works like a lever rotating around a central fulcrum (the axle).

A hydraulic jack has an input piston area of 2 sq in and an output piston area of 20 sq in. A force of 50 lb on the input produces how much output force?

Answer: 500 lb

Pascal's Law: output force = input force × (output area / input area) = 50 × (20/2) = 500 lb.

A compound gear train has a first pair with a 2:1 ratio and a second pair with a 4:1 ratio. What is the overall ratio?

Answer: 8:1

In a compound gear train, multiply the individual ratios: 2 × 4 = 8:1 overall.

Which material property describes a material's ability to return to its original shape after a load is removed?

Answer: Elasticity

Elasticity is the ability of a material to recover its original shape and size after deforming stress is removed.

A centrifugal pump impeller spins faster. What happens to the fluid pressure it produces?

Answer: Pressure increases

Higher impeller speed imparts more kinetic energy to the fluid, which converts to greater pressure at the pump outlet.

When two shafts must transmit power at a slight angle to each other, which coupling is used?

Answer: Universal joint (U-joint)

A universal joint allows power transmission between shafts that are not perfectly aligned or are at an angle to each other.

A container holds oil (density 0.8) and water (density 1.0). Where does the oil settle?

Answer: At the top

Fluids with lower density float on fluids with higher density, so oil settles above water.

A beam is supported at both ends with a load placed at the center. Where is the bending stress greatest?

Answer: At the center of the beam

For a simply supported beam with a center point load, maximum bending moment — and therefore maximum bending stress — occurs at the midpoint.

Which valve type provides the most gradual and precise flow control in a piping system?

Answer: Globe valve

Globe valves have a plug that moves perpendicular to flow, allowing fine incremental adjustment of flow rate.

A V-belt drive slips when the load is too high. What is the most effective solution?

Answer: Increase belt tension or install a wider/higher-capacity belt

Slipping means the belt cannot transmit the required torque; increasing tension or using a higher-capacity belt restores grip.

Two pistons in a hydraulic system: piston A has an area of 5 sq in and piston B has an area of 25 sq in. If piston A moves 10 inches, how far does piston B move?

Answer: 2 inches

Volume is conserved: A_A × d_A = A_B × d_B → 5×10 = 25×d_B → d_B = 2 inches.

What does a torque wrench measure?

Answer: The rotational force applied to a fastener

A torque wrench measures and limits the rotational force (torque) applied when tightening fasteners to a specified value.

In a pulley system, if you pull the rope 6 feet to raise a load 2 feet, what is the mechanical advantage?

Answer: 3

Mechanical advantage = distance effort moves / distance load moves = 6 ft / 2 ft = 3.

A shaft rotates clockwise when viewed from one end. When viewed from the opposite end, it rotates:

Answer: Counterclockwise

The rotation direction reverses when you view a shaft from the opposite end, just as a clock face appears to run backwards from behind.

Which bearing type is best suited for handling large axial (thrust) loads in one direction?

Answer: Tapered roller bearing

Tapered roller bearings are designed to handle combined radial and axial loads, making them ideal for high thrust applications.