WTMA - Wiesen Test of Mechanical Aptitude — Questions and Answers

Question 1: Two identical blocks are connected by a rope and pulled across a frictionless surface by a 20 N force. What is the tension in the rope between the blocks?

10 N (Correct answer)
20 N
5 N
40 N

Correct answer: 10 N

The rope must accelerate only one block (half the total mass), so tension is half the applied force: 20 N ÷ 2 = 10 N.

Question 2: Which of the following best describes potential energy?

Energy of motion
Stored energy due to position or condition (Correct answer)
Heat released by friction
Energy lost to sound

Correct answer: Stored energy due to position or condition

Potential energy is stored energy that an object has due to its position, shape, or condition.

Question 3: A screwdriver is turned 10 full rotations to drive a screw 0.5 inches into wood. What is the thread pitch of the screw?

0.5 inches per turn
5 inches per turn
0.05 inches per turn (Correct answer)
0.025 inches per turn

Correct answer: 0.05 inches per turn

Thread pitch = total distance ÷ number of turns = 0.5 ÷ 10 = 0.05 inches per turn.

Question 4: Two identical wheels are connected by their axles via a rigid rod (like a car axle). When the vehicle turns left, which wheel must rotate faster?

Both rotate at the same speed
The left wheel
The right wheel (Correct answer)
Neither — they slide instead

Correct answer: The right wheel

In a left turn, the right (outer) wheel travels a longer arc and must rotate faster than the inner left wheel.

Question 5: Which type of wrench provides the most torque with the least chance of rounding off a bolt head?

Adjustable wrench
Needle-nose pliers
Open-end wrench
Box-end wrench (Correct answer)

Correct answer: Box-end wrench

A box-end (closed) wrench grips all six sides of a hex bolt, distributing force evenly and minimizing slippage.

Question 6: One horsepower is equal to which of the following?

1,000 watts
Both 550 ft-lb/s and 33,000 ft-lb/min (Correct answer)
550 ft-lb per second only
33,000 ft-lb per minute

Correct answer: Both 550 ft-lb/s and 33,000 ft-lb/min

One horsepower equals 550 ft-lb/s, which is equivalent to 33,000 ft-lb/min (550 × 60).

Question 7: A construction worker places sandbags at the base of a portable sign to prevent it from tipping over. The sandbags improve stability by:

Lowering the center of gravity and widening the effective base (Correct answer)
Eliminating the sign's torque entirely
Raising the center of gravity of the sign system
Reducing wind resistance on the sign

Correct answer: Lowering the center of gravity and widening the effective base

Sandbags add low mass that lowers the combined center of gravity and increases resistance to tipping by anchoring the base.

Question 8: A mechanic uses a pry bar to move a heavy engine block. When the fulcrum (pivot) is placed closer to the engine block, the force the mechanic must apply:

Decreases because the load is closer to the pivot
Increases because the lever arm is shorter on the effort side (Correct answer)
Increases because the engine is too heavy to leverage
Stays the same regardless of fulcrum position

Correct answer: Increases because the lever arm is shorter on the effort side

Moving the fulcrum closer to the load shortens the load arm but also shortens the effort arm even more, requiring greater force from the mechanic.

Question 9: A compound gear train has three gears in sequence: Gear 1 (40 teeth) drives Gear 2 (10 teeth), which shares an axle with Gear 3 (30 teeth), which drives Gear 4 (15 teeth). What is the overall speed ratio (Gear 4 speed / Gear 1 speed)?

8:1 (Correct answer)
4:1
16:1
2:1

Correct answer: 8:1

Stage 1 ratio: 40/10 = 4; Stage 2 ratio: 30/15 = 2; overall = 4 × 2 = 8, so Gear 4 spins 8 times faster than Gear 1.

Question 10: A wrench handle is extended by adding a longer handle. How does this affect the force needed to turn a bolt?

The same force is needed
More force is needed
Less force is needed (Correct answer)
Force is no longer relevant

Correct answer: Less force is needed

A longer handle increases the moment arm (torque), allowing the same bolt to be turned with less applied force.

Question 11: Which factor does NOT affect the resistance of a wire?

Color of the wire's insulation (Correct answer)
Material of the wire
Cross-sectional area of the wire
Length of the wire

Correct answer: Color of the wire's insulation

The insulation color is a labeling convention only; resistance depends on length, material, and cross-sectional area.

Question 12: A motor lifts a 500 lb load 10 feet in 5 seconds. What is the power output?

2,500 ft-lb/s
500 ft-lb/s
250 ft-lb/s
1,000 ft-lb/s (Correct answer)

Correct answer: 1,000 ft-lb/s

Power = (Force × Distance) / Time = (500 × 10) / 5 = 1,000 ft-lb/s.

Question 13: Which of the following best describes static friction compared to kinetic friction on the same surfaces?

Static friction only acts on vertical surfaces
They are always equal
Kinetic friction is greater than static friction
Static friction is greater than kinetic friction (Correct answer)

Correct answer: Static friction is greater than kinetic friction

Static friction is generally greater than kinetic friction because it takes more force to start an object moving than to keep it moving.

Question 14: Which of the following tools would be best suited for tightening a bolt?

Screwdriver
Pliers
Hamer
Wrench (Correct answer)

Correct answer: Wrench

A wrench is the ideal tool for tightening a bolt because it is specifically designed to grip the hexagonal or square head of a bolt or nut. It provides the necessary leverage and secure hold to apply torque, ensuring the bolt is tightened effectively and safely. Other tools like screwdrivers or hammers serve different functions.

Question 15: Which of the following best describes mechanical advantage gained from a wheel-and-axle system?

The axle diameter must equal the wheel diameter
The axle always moves faster than the wheel
Turning the larger wheel requires less force to overcome load on the smaller axle (Correct answer)
The wheel and axle always rotate at the same speed

Correct answer: Turning the larger wheel requires less force to overcome load on the smaller axle

A large wheel provides mechanical advantage by allowing a small input force over a large radius to overcome a larger load at the smaller axle radius.

Question 16: If two identical springs (each with spring constant k) are connected in parallel, what is the combined spring constant?

k/2
4k
2k (Correct answer)
k

Correct answer: 2k

Springs in parallel add their constants directly, so the combined constant is k + k = 2k.

Question 17: Two wheels of different sizes are connected by an axle (fixed together). A rope is wrapped around the larger wheel and a load hangs from a rope on the smaller axle. When the larger wheel is turned, the load:

Rises but requires more force than the load's weight
Rises with less input force than the load's weight (Correct answer)
Descends regardless of direction of turn
Remains stationary

Correct answer: Rises with less input force than the load's weight

The large wheel provides mechanical advantage: input force × wheel radius = load × axle radius, so less force is needed than the load's actual weight.

Question 18: A conveyor belt moves at 10 ft/min and is driven by a drum 1 foot in diameter. The drum's rotational speed is approximately:

3.18 RPM (Correct answer)
31.4 RPM
10 RPM
6.28 RPM

Correct answer: 3.18 RPM

Belt speed = RPM × circumference; RPM = 10 ÷ (π × 1) ≈ 10 ÷ 3.14 ≈ 3.18 RPM.

Question 19: A battery's voltage represents which of the following?

The resistance of the battery
The amount of charge stored
The electrical pressure that pushes current through a circuit (Correct answer)
The current the battery provides

Correct answer: The electrical pressure that pushes current through a circuit

Voltage (electromotive force) is the electrical pressure or potential difference that drives current through a circuit.

Question 20: Which of the following is an example of an electrical insulator?

Iron
Plastic (Correct answer)
Aluminum
Salt water

Correct answer: Plastic

Plastic has very high resistance and does not allow current to flow easily, making it a good insulator.

Question 21: A mechanic is adjusting a machine part and notices it always rolls to the same side when released on a flat surface. This tells her that the part's center of gravity is:

Evenly distributed throughout
Exactly at its geometric center
At the top of the part
Offset to the side it rolls toward (Correct answer)

Correct answer: Offset to the side it rolls toward

Objects roll toward their center of gravity; if a part consistently rolls to one side, the center of gravity is offset in that direction.

Question 22: A worm gear set has a worm with 1 start and a worm wheel with 40 teeth. The gear ratio is:

1:1
40:1 (Correct answer)
20:1
1:40

Correct answer: 40:1

Worm gear ratio = worm wheel teeth ÷ worm starts = 40 ÷ 1 = 40:1, meaning the worm turns 40 times for each rotation of the wheel.

Question 23: Which of the following actions results in the greatest increase in an object's gravitational potential energy?

Sliding a 10 kg box horizontally across a 5-meter floor.
Compressing a spring by 10 centimeters.
Lifting a 5 kg box onto a 2-meter high shelf. (Correct answer)
Lowering a 20 kg box from a truck to the ground.

Correct answer: Lifting a 5 kg box onto a 2-meter high shelf.

Gravitational potential energy depends on mass, gravity, and height (PE = mgh). Lifting the 5 kg box 2 meters high increases its height against gravity, thus increasing its potential energy. Sliding the box horizontally does not change its height. Compressing a spring increases elastic potential energy, not gravitational. Lowering a box decreases its gravitational potential energy.

Question 24: Which modification to a metal rod would MOST increase the amount of heat it can conduct per minute?

Increasing its cross-sectional area (Correct answer)
Painting it black
Decreasing the temperature difference across it
Wrapping it in fiberglass

Correct answer: Increasing its cross-sectional area

Larger cross-sectional area provides more pathways for heat to flow, increasing total conduction rate.

Question 25: A heavy crate and a light box are pushed with the same force on the same surface. Which accelerates faster?

Neither accelerates
The heavy crate
The light box (Correct answer)
Both accelerate equally

Correct answer: The light box

From Newton's second law (a = F/m), a smaller mass produces greater acceleration when the same force is applied.

Question 26: What is a 'UNC' thread designation in the US fastener system?

Universal non-corrosive thread
Unified National Cylindrical thread
Unified National Coarse thread (Correct answer)
Ultra-narrow coarse thread

Correct answer: Unified National Coarse thread

UNC stands for Unified National Coarse, a standard thread series with fewer threads per inch than UNF (fine) threads.

Question 27: In a house with a central heating system, a vent blows hot air into a room. The warm air rises, and cooler air sinks to take its place, creating a circular flow. This process of heat distribution is called:

Convection (Correct answer)
Conduction
Thermal resistance
Radiation

Correct answer: Convection

Convection is the transfer of heat through the movement of fluids (liquids or gases). In this scenario, the hot air is less dense and rises, while the cooler, denser air sinks, creating a convection current that circulates heat throughout the room.

Question 28: Two pipes carry the same hot fluid. Pipe A has twice the wall thickness of Pipe B, made of the same material. Which pipe loses more heat per hour through its walls?

Pipe A, because thicker walls conduct more total heat
Pipe A, because it has more material to store heat
Both lose heat at the same rate
Pipe B, because thinner walls offer less resistance to heat flow (Correct answer)

Correct answer: Pipe B, because thinner walls offer less resistance to heat flow

Thinner walls have lower thermal resistance, allowing more heat to conduct through per unit time.

Question 29: A lever has its fulcrum positioned 1 foot from a 100-lb load and 4 feet from the effort point. How much force is needed to lift the load?

100 lbs
25 lbs (Correct answer)
400 lbs
50 lbs

Correct answer: 25 lbs

Using the lever principle, effort × effort arm = load × load arm, so effort = 100 × 1 ÷ 4 = 25 lbs.

Question 30: Two resistors of 6 ohms each are connected in series. What is the total resistance?

6 ohms
12 ohms (Correct answer)
3 ohms
36 ohms

Correct answer: 12 ohms

In a series circuit, total resistance is the sum of all resistors: 6 + 6 = 12 ohms.

Question 31: Which factor does NOT affect a coil spring's stiffness?

Number of active coils
Wire diameter
Coil diameter
Color of the wire (Correct answer)

Correct answer: Color of the wire

Wire diameter, coil diameter, and number of active coils all affect spring stiffness; wire color has no effect.

Question 32: Which of the following materials is the best thermal conductor, meaning it allows heat to pass through it most easily?

Air
Styrofoam
Copper (Correct answer)
Wood

Correct answer: Copper

Metals are excellent thermal conductors because of their free-moving electrons, which efficiently transfer thermal energy. Copper is a metal known for its high thermal conductivity, while wood, styrofoam, and air are all considered thermal insulators.

Question 33: A directional control valve in a hydraulic system is used to:

Filter fluid contaminants
Regulate system pressure
Control which way a cylinder extends or retracts (Correct answer)
Measure flow rate

Correct answer: Control which way a cylinder extends or retracts

Directional control valves route fluid to one side of a cylinder or the other to control direction of motion.

Question 34: In a horizontal pipe, water flows from a wider section into a narrower section. According to Bernoulli's principle, what happens to the water's speed and pressure as it enters the narrower section?

Speed decreases, pressure decreases
Speed increases, pressure increases
Speed increases, pressure decreases (Correct answer)
Speed decreases, pressure increases

Correct answer: Speed increases, pressure decreases

Bernoulli's principle states that for a fluid in motion, an increase in speed occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy. In a horizontal pipe, when the cross-sectional area decreases, the fluid must speed up to maintain the same volume flow rate (the principle of continuity). As the speed increases, the internal pressure of the fluid decreases.

Question 35: Which tool is used to measure the outside diameter of a shaft accurately to thousandths of an inch?

Outside micrometer (Correct answer)
Vernier caliper
Feeler gauge
Dial indicator

Correct answer: Outside micrometer

An outside micrometer is designed to precisely measure the external diameter of cylindrical objects to 0.001 inch or finer.

Question 36: Two identical springs (spring constant k each) are connected end-to-end in series. What is the combined spring constant?

2k
k/2 (Correct answer)
4k
k

Correct answer: k/2

Springs in series have a combined constant of 1/(1/k + 1/k) = k/2, making the assembly more flexible than either spring alone.

Question 37: A 10 lb object is dropped from a height of 20 feet. Just before it hits the ground, approximately how much kinetic energy does it have (ignoring air resistance)?

10 ft-lb
2,000 ft-lb
200 ft-lb (Correct answer)
20 ft-lb

Correct answer: 200 ft-lb

The potential energy at the top (10 × 20 = 200 ft-lb) converts entirely to kinetic energy just before impact.

Question 38: Which direction does conventional current flow in a circuit?

In both directions at once
Only through insulators
From positive terminal to negative terminal (Correct answer)
From negative terminal to positive terminal

Correct answer: From positive terminal to negative terminal

By convention, current is defined as flowing from the positive terminal through the external circuit to the negative terminal.

Question 39: Which of the following best describes the fundamental purpose of a solid axle in a simple two-wheel cart?

To connect the wheels and ensure they rotate together at the same rate. (Correct answer)
To act as the primary braking mechanism.
To reduce the overall weight of the cart.
To provide suspension for a smoother ride.

Correct answer: To connect the wheels and ensure they rotate together at the same rate.

The axle is a rigid rod that connects the two wheels. Its primary function is to transfer rotational motion and force, compelling both wheels to spin at the same speed. This ensures the cart moves in a straight line when pushed or pulled.

Question 40: Which of the following properties of a fluid is a measure of its internal resistance to flow?

Viscosity (Correct answer)
Buoyancy
Compressibility
Density

Correct answer: Viscosity

Viscosity is the measure of a fluid's internal friction or resistance to flow. A fluid with high viscosity, like honey, flows slowly, while a fluid with low viscosity, like water, flows easily. Density is mass per unit volume, buoyancy is the upward force exerted by a fluid, and compressibility is the ability to be squeezed into a smaller volume.

Question 41: What does a higher grade number on a metric bolt (e.g., 10.9 vs 8.8) indicate?

Higher strength and hardness (Correct answer)
Corrosion-resistant coating
Finer thread specification
Larger thread pitch

Correct answer: Higher strength and hardness

Higher metric bolt grade numbers (like 10.9 or 12.9) indicate greater tensile strength and hardness compared to lower grades like 8.8.

Question 42: In the gear system shown, the driver gear (A) rotates clockwise. An idler gear (B) is placed between gear A and the driven gear (C). In which direction will gear C rotate?

Clockwise (Correct answer)
It will alternate directions
Counter-clockwise
It will not rotate

Correct answer: Clockwise

When two gears mesh directly, they rotate in opposite directions. Therefore, if driver gear A rotates clockwise, idler gear B will rotate counter-clockwise. Since gear B (counter-clockwise) meshes with gear C, gear C will rotate in the opposite direction, which is clockwise. The primary function of a single idler gear is to make the driver and driven gears rotate in the same direction.

Question 43: Water flows through a pipe that narrows from 4 inches to 2 inches in diameter. What happens to the flow velocity in the narrow section?

It doubles
It quadruples (Correct answer)
It stays the same
It halves

Correct answer: It quadruples

Area decreases by a factor of 4 (diameter halved), so by continuity the velocity quadruples.

Question 44: What tool is used to extract a broken bolt that has snapped off flush with or below the surface?

Tap
Reamer
Center punch
Ez-out / screw extractor (Correct answer)

Correct answer: Ez-out / screw extractor

A screw extractor (Ez-out) is drilled into the broken bolt and then turned in reverse to grip and remove the broken fastener.

Question 45: An airplane loads cargo into the rear of the fuselage, moving the plane's center of gravity toward the tail. This makes the plane:

More maneuverable and easier to control
Nose-heavy, requiring more thrust
Tail-heavy, requiring corrective control inputs to maintain level flight (Correct answer)
More fuel efficient due to reduced drag

Correct answer: Tail-heavy, requiring corrective control inputs to maintain level flight

A rearward center of gravity makes an aircraft tail-heavy and less stable longitudinally, requiring constant forward elevator correction.

Question 46: Which shape has the lowest center of gravity relative to its height?

A sphere resting on a flat surface
A wide flat cone with the base at the bottom (Correct answer)
A cube balanced on one corner
A tall thin cylinder

Correct answer: A wide flat cone with the base at the bottom

A wide flat cone with its base down has most of its mass concentrated near the base, placing the center of gravity very low.

Question 47: A nail is easier to drive into wood at the tip than a flat surface because of:

Reduced area increasing pressure (Correct answer)
Greater friction
Greater mass
Magnetic attraction

Correct answer: Reduced area increasing pressure

The pointed tip concentrates the same driving force over a very small area, creating high pressure that penetrates the wood fibers.

Question 48: A vehicle suspension spring supports 800 lbs and compresses 4 inches. What is its spring constant?

200 lb/in (Correct answer)
3,200 lb/in
400 lb/in
100 lb/in

Correct answer: 200 lb/in

Spring constant k = F/x = 800 lb / 4 in = 200 lb/in.

Question 49: A person is trying to push a heavy crate across a floor but it does not move. Which type of friction is preventing the crate from moving?

Static friction (Correct answer)
Fluid friction
Rolling friction
Kinetic friction

Correct answer: Static friction

Static friction is the force that opposes the initiation of motion between two surfaces in contact. Since the crate is not moving despite the applied force, static friction is the force that is counteracting the push. Kinetic friction applies only when an object is already in motion.

Question 50: A worker needs to cut a metal rod. Which of the following hand tools is most appropriate for this task?

Backsaw
Coping saw
Keyhole saw
Hacksaw (Correct answer)

Correct answer: Hacksaw

A hacksaw is a fine-toothed saw designed specifically for cutting metal. Its blade is held under tension in a frame. A coping saw is for intricate cuts in wood, a backsaw is for precise woodworking joints, and a keyhole saw is for cutting small, awkward holes.

Question 51: If the force applied to an object is doubled, while its mass remains constant, what is the effect on its acceleration?

It is quartered.
It is halved.
It remains the same.
It is doubled. (Correct answer)

Correct answer: It is doubled.

This question relates to Newton's Second Law of Motion, which states that Force = Mass × Acceleration (F=ma). If the mass (m) is constant, acceleration (a) is directly proportional to the force (F). Therefore, if the force is doubled, the acceleration must also double to maintain the equality.

Question 52: Two hydraulic cylinders are connected in parallel to the same pump. Compared to a single cylinder, what is true about force and speed?

Force and speed are both unchanged
Force per cylinder is the same, but each extends at half the speed (Correct answer)
Each cylinder exerts double the force at the same speed
Force is halved and speed doubles

Correct answer: Force per cylinder is the same, but each extends at half the speed

In parallel, pressure (and thus force) is the same, but pump flow is split, so each cylinder extends more slowly.

Question 53: A pulley system is used to lift a 300 N load with only 150 N of effort. What is the mechanical advantage?

300
0.5
150
2 (Correct answer)

Correct answer: 2

Mechanical advantage equals load force divided by effort force: 300 N ÷ 150 N = 2.

Question 54: Which situation has the LEAST friction?

A wooden block slid across rough concrete
A rubber stopper dragged across asphalt
A brick dragged across a brick surface
A steel ball bearing rolling in a steel race (Correct answer)

Correct answer: A steel ball bearing rolling in a steel race

Ball bearings are specifically designed to minimize friction through rolling contact and smooth, hardened steel surfaces.

Question 55: Gear A is turning clockwise and is meshed directly with Gear B. Gear B is on the same axle as Gear C, which is smaller. Gear C is meshed directly with Gear D. In which direction is Gear D turning?

It will not turn.
Clockwise (Correct answer)
The direction is indeterminate.
Counter-clockwise

Correct answer: Clockwise

If Gear A is clockwise, Gear B (meshed with A) must turn counter-clockwise. Since Gear C is on the same axle as Gear B, it also turns counter-clockwise. Because Gear D is meshed with Gear C, it must turn in the opposite direction, which is clockwise.

Question 56: A hydraulic system is designed to be 'fail-safe', meaning a small leak should not cause an immediate and catastrophic failure. Which type of fluid would be MOST suitable for this system?

A fluid with very low density
A fluid with very high viscosity
A highly compressible gas (like air)
A nearly incompressible liquid (like oil) (Correct answer)

Correct answer: A nearly incompressible liquid (like oil)

Hydraulic systems rely on Pascal's principle, which works because liquids are nearly incompressible. Using a nearly incompressible fluid like oil ensures that when force is applied to one piston, the pressure is transmitted efficiently to the other. A gas would compress under pressure, storing energy instead of transmitting force, and a small leak would cause a rapid loss of pressure and system failure. Viscosity and density are less critical to the fundamental operation than incompressibility.

Question 57: Two identical balls are dropped from different heights. Ball A is dropped from 10 feet; Ball B from 20 feet. Compare their speeds just before hitting the ground.

Ball B is about 1.4 times faster than Ball A (Correct answer)
Ball A is faster
Ball B is twice as fast as Ball A
Both hit at the same speed

Correct answer: Ball B is about 1.4 times faster than Ball A

Speed is proportional to the square root of height (v = √(2gh)), so doubling height increases speed by √2 ≈ 1.4 times.

Question 58: Three 9-ohm resistors are connected in parallel. What is the total resistance?

1 ohm
27 ohms
9 ohms
3 ohms (Correct answer)

Correct answer: 3 ohms

For identical resistors in parallel, total resistance = R/n = 9 Ω ÷ 3 = 3 ohms.

Question 59: A sled slides down a snowy hill and reaches the flat ground. What eventually stops it on the flat?

Friction between sled runners and snow (Correct answer)
Normal force increasing
Gravity reversing direction
Momentum running out naturally

Correct answer: Friction between sled runners and snow

Friction between the sled runners and the snow acts opposite to the direction of motion, gradually decelerating the sled to a stop.

Question 60: A car engine crankshaft converts which type of motion to rotational motion?

Linear (reciprocating) to rotational (Correct answer)
Rotational to linear
Oscillating to linear
Rotational to oscillating

Correct answer: Linear (reciprocating) to rotational

The crankshaft converts the up-and-down (reciprocating) motion of pistons into the rotational motion that drives the wheels.

WTMA - Wiesen Test of Mechanical Aptitude

The Wiesen Test of Mechanical Aptitude (WTMA) is a 60-question, 30-minute pre-employment assessment published by Criteria Corp. It measures mechanical reasoning through illustrated multiple-choice items covering forces, fluid mechanics, pulleys, gears, electricity, and everyday tool knowledge. No penalty for incorrect answers.

Questions

30 min

Time Limit

80%

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