WTMA - Wiesen Test of Mechanical Aptitude — Questions and Answers

Question 1: A directional control valve in a hydraulic system is used to:

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

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 2: Which surface combination would produce the HIGHEST coefficient of friction?

Rubber on concrete (Correct answer)
Steel on ice
Ball bearings on steel
Waxed wood on waxed wood

Correct answer: Rubber on concrete

Rubber on concrete has a very high coefficient of friction due to the soft, grippy nature of rubber and the rough texture of concrete.

Question 3: Which unit is commonly used to measure electrical power?

Watt (Correct answer)
Joule
Pascal
Newton

Correct answer: Watt

The watt (W) is the SI unit of power, including electrical power, equal to one joule per second.

Question 4: A pulley system is used to lift a 300 N load with only 150 N of effort. What is the mechanical advantage?

300
2 (Correct answer)
150
0.5

Correct answer: 2

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

Question 5: In a pulley system, a worker pulls 6 feet of rope to raise a load 2 feet. What is the mechanical advantage?

2
12
3 (Correct answer)
6

Correct answer: 3

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

Question 6: Oil is applied to a machine's moving parts. What effect does this have on friction?

It reduces friction by creating a lubricating film (Correct answer)
It converts kinetic friction to static friction
It has no effect on friction
It increases friction to prevent slipping

Correct answer: It reduces friction by creating a lubricating film

Lubrication separates surfaces with a thin oil film, greatly reducing the coefficient of friction between moving parts.

Question 7: If the driving pulley is larger in diameter than the driven pulley, the driven shaft will:

Rotate faster than the driving shaft (Correct answer)
Rotate slower than the driving shaft
Rotate at the same speed as the driving shaft
Rotate in the opposite direction

Correct answer: Rotate faster than the driving shaft

A smaller driven pulley must complete more revolutions to cover the same belt distance as the larger driver, so it rotates faster — acting as a speed increaser.

Question 8: Which of the following lever classes always provides a mechanical advantage greater than 1, meaning the output force is always greater than the effort force?

Third-Class Lever
All classes can provide this advantage
First-Class Lever
Second-Class Lever (Correct answer)

Correct answer: Second-Class Lever

A second-class lever has the load (resistance) positioned between the fulcrum and the effort. This arrangement ensures the effort arm is always longer than the load arm, resulting in a mechanical advantage that is always greater than 1.

Question 9: A motor lifts a 500 lb load 10 feet in 5 seconds. What is the power output?

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

Correct answer: 1,000 ft-lb/s

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

Question 10: If voltage across a resistor doubles while resistance stays the same, what happens to the current?

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

Correct answer: It doubles

By Ohm's Law (I = V/R), doubling V while R stays constant doubles the current.

Question 11: A spring is compressed by a distance 'x', storing an amount of elastic potential energy 'E'. If the same spring is instead compressed by a distance of '2x', how much elastic potential energy will it store?

E (the same amount)
4E (quadruple the amount) (Correct answer)
2E (double the amount)
E/2 (half the amount)

Correct answer: 4E (quadruple the amount)

The formula for elastic potential energy stored in a spring is PE = ½kx². This shows that the energy is proportional to the square of the displacement (x²). If you double the displacement from 'x' to '2x', the new energy will be proportional to (2x)², which is 4x². Therefore, the stored energy is quadrupled (multiplied by 4).

Question 12: Two objects with different masses are dropped from the same height in a vacuum. Which hits the ground first?

They hit at the same time (Correct answer)
It depends on their shape
The heavier object
The lighter object

Correct answer: They hit at the same time

In a vacuum, gravity accelerates all objects equally regardless of mass (9.8 m/s²), so both objects fall at identical rates and land simultaneously.

Question 13: A rubber bumper on a car absorbs impact energy. Which physical property makes rubber effective for this purpose?

High thermal conductivity
High rigidity
Low density
High elasticity and energy absorption (Correct answer)

Correct answer: High elasticity and energy absorption

Rubber's high elasticity allows it to deform under impact and absorb energy, then return to its original shape without transferring all force to the vehicle.

Question 14: A tightrope walker often carries a long pole. How does this pole help them maintain balance?

It effectively lowers the walker's combined center of gravity. (Correct answer)
It makes the walker more aerodynamic.
The pole's weight pushes them down onto the rope more firmly.
It increases the walker's total mass, making them harder to move.

Correct answer: It effectively lowers the walker's combined center of gravity.

The long pole, especially if it has weights at the ends and is held low, lowers the combined center of gravity of the walker and the pole. [6] A lower center of gravity increases stability, making it easier for the walker to make small adjustments and stay balanced on the narrow rope. [8]

Question 15: Two bicycles, A and B, are traveling side-by-side at the exact same speed. Bicycle A has larger wheels than Bicycle B. Which statement is true about the rotation of the wheels?

The wheels of Bicycle A are rotating at a slower RPM. (Correct answer)
The wheels of Bicycle B are rotating at a slower RPM (revolutions per minute).
The wheels of both bicycles are rotating at the same RPM.
The size of the wheel does not affect the RPM at a constant speed.

Correct answer: The wheels of Bicycle A are rotating at a slower RPM.

To cover the same linear distance per unit of time (speed), a wheel with a larger circumference needs to complete fewer revolutions than a wheel with a smaller circumference. Therefore, the larger wheels of Bicycle A rotate at a slower RPM to keep the same speed as Bicycle B.

Question 16: Two workers push a crate from opposite sides with equal force. What is the result?

The crate spins in place
The crate does not move (Correct answer)
The crate accelerates toward the stronger worker
Friction increases dramatically

Correct answer: The crate does not move

Equal and opposite forces produce a net force of zero, so the crate remains stationary (assuming it was at rest).

Question 17: Two resistors of 6 ohms each are connected in series. What is the total resistance?

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

Correct answer: 12 ohms

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

Question 18: Which of the following is an example of an electrical insulator?

Plastic (Correct answer)
Salt water
Aluminum
Iron

Correct answer: Plastic

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

Question 19: A circuit has a 9-volt battery and a resistor. If 0.5 amperes flow, what is the resistance?

4.5 ohms
9.5 ohms
0.055 ohms
18 ohms (Correct answer)

Correct answer: 18 ohms

Using Ohm's Law: R = V/I = 9 V ÷ 0.5 A = 18 ohms.

Question 20: 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?

Counter-clockwise
It will alternate directions
Clockwise (Correct answer)
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 21: A rectangular block is tipped until it balances on its corner. At that tipping point, the center of gravity is located:

At the geometric center of the block
Directly above the pivot corner (Correct answer)
Below the pivot corner
At the midpoint of the base

Correct answer: Directly above the pivot corner

An object is at the tipping point when its center of gravity is directly over the pivot point — any further tipping causes it to fall.

Question 22: A modern race car is designed to be very low to the ground with a wide wheelbase. What is the primary physical principle behind this design for enhancing stability?

To make it easier for the driver to enter and exit the vehicle.
To reduce aerodynamic drag and improve top speed.
To increase its overall mass for better road grip.
To lower its center of gravity and widen its base of support. (Correct answer)

Correct answer: To lower its center of gravity and widen its base of support.

Stability is increased by lowering an object's center of gravity and widening its base of support. [8, 9] A low and wide design makes the race car much more resistant to tipping or rolling over, especially during high-speed turns. [14]

Question 23: 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)?

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

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 24: What is the primary purpose of a hydraulic filter?

Prevent fluid from flowing backward
Remove contaminant particles that cause wear in valves and pumps (Correct answer)
Regulate pressure throughout the system
Cool the hydraulic fluid

Correct answer: Remove contaminant particles that cause wear in valves and pumps

Filters remove solid particles from the fluid to prevent abrasive wear and clogging of precision hydraulic components.

Question 25: Water stored behind a dam is an example of which type of energy?

Nuclear energy
Gravitational potential energy (Correct answer)
Thermal energy
Kinetic energy

Correct answer: Gravitational potential energy

Water elevated behind a dam has gravitational potential energy due to its height above the turbines below.

Question 26: Which of the following properties of a fluid is a measure of its internal resistance to flow?

Buoyancy
Viscosity (Correct answer)
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 27: 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?

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

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 28: Which statement best describes the purpose of a torque wrench?

It removes bolts faster than a standard wrench
It applies a precisely measured rotational force to a fastener (Correct answer)
It grips rounded bolt heads better
It extends reach into tight spaces

Correct answer: It applies a precisely measured rotational force to a fastener

A torque wrench measures and limits the rotational force applied to a fastener, preventing over-tightening that can strip threads or break bolts.

Question 29: Which tool is used to measure the outside diameter of a shaft accurately to thousandths of an inch?

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

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 30: Hydraulic fluid must be incompressible for the system to work properly. Why?

So the fluid stays cool under pressure
So the fluid does not mix with air
So force is transmitted instantly without energy loss to compression (Correct answer)
So the fluid can lubricate moving parts

Correct answer: So force is transmitted instantly without energy loss to compression

Incompressible fluid transmits force directly; a compressible fluid would absorb energy before moving the load.

Question 31: A flywheel spins at high speed to store energy. This is an example of:

Chemical potential energy
Elastic potential energy
Nuclear energy
Rotational kinetic energy (Correct answer)

Correct answer: Rotational kinetic energy

A spinning flywheel stores rotational kinetic energy, which can be released to do work.

Question 32: What is the purpose of a pilot hole when driving a wood screw?

It increases the holding strength by compressing wood fibers
It prevents the wood from splitting and guides the screw straight (Correct answer)
It pre-cuts the threads so the screw needs less torque
It countersinks the screw head automatically

Correct answer: It prevents the wood from splitting and guides the screw straight

A pilot hole drilled slightly smaller than the screw shank prevents wood splitting and guides the screw into proper alignment.

Question 33: A blacksmith's iron tongs feel hot after gripping a heated piece of metal. This is an example of:

Radiation from the flame
Evaporative cooling
Convection through the air
Conduction through direct contact (Correct answer)

Correct answer: Conduction through direct contact

Heat transferred from the hot metal directly into the tongs through contact is conduction.

Question 34: An object is moving at constant velocity on a surface. What must be true about the forces acting on it?

Friction force is zero
Net force is zero (Correct answer)
Applied force exceeds friction
Gravity is absent

Correct answer: Net force is zero

By Newton's first law, constant velocity means no acceleration, which requires the net force to be zero — applied force equals friction.

Question 35: A steel bolt conducts more heat than a rubber gasket of the same size because steel has:

More surface area
Greater hardness
Lower density
Higher thermal conductivity (Correct answer)

Correct answer: Higher thermal conductivity

Thermal conductivity is the material property that determines how well a substance conducts heat.

Question 36: Which fastener is specifically designed to prevent rotation using a non-circular shank that fits a matching hole?

Hex bolt
Shoulder bolt
Carriage bolt (Correct answer)
Eye bolt

Correct answer: Carriage bolt

A carriage bolt has a square shoulder under its round domed head that embeds into wood (or a square hole in metal) to prevent rotation while tightening the nut.

Question 37: A rack and pinion converts:

Rotational motion to linear motion (and vice versa) (Correct answer)
Rotational motion to linear motion
Rotational motion to rotational motion
Linear motion to rotational motion only

Correct answer: Rotational motion to linear motion (and vice versa)

A rack and pinion can convert rotational to linear motion and linear to rotational, depending on which part is driven.

Question 38: A bicycle has a front chainring with 48 teeth and a rear sprocket with 16 teeth. How many times does the rear wheel rotate for each pedal revolution?

48
0.33
3 (Correct answer)
1

Correct answer: 3

Speed ratio = driver teeth / driven teeth = 48/16 = 3, so the rear wheel makes 3 revolutions per pedal revolution.

Question 39: If more coils are added to a coil spring while keeping the wire diameter and coil diameter the same, the spring becomes:

Stiffer
More flexible (Correct answer)
Stronger
Shorter

Correct answer: More flexible

More active coils means more material available to flex, reducing the spring constant and making the spring easier to deflect.

Question 40: A 200-pound crate is pushed 15 feet along a level floor. How much work is done against gravity?

0 ft-lb (Correct answer)
3,000 ft-lb
200 ft-lb
15 ft-lb

Correct answer: 0 ft-lb

No work is done against gravity when an object moves horizontally, since gravity acts vertically.

Question 41: 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:

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

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 42: What is the primary purpose of a ground wire in an electrical system?

To provide a safe path for fault current and prevent shock (Correct answer)
To add resistance to the circuit
To store extra charge
To increase circuit voltage

Correct answer: To provide a safe path for fault current and prevent shock

A ground wire provides a low-resistance return path for fault current, protecting people from electric shock if a fault occurs.

Question 43: An object is pushed across a rough, horizontal surface at a constant velocity. Which of the following statements is true regarding the forces acting on the object?

The net force on the object is greater than zero.
The applied force is greater than the force of friction.
The force of gravity is less than the normal force.
The force of friction is equal to the applied force. (Correct answer)

Correct answer: The force of friction is equal to the applied force.

According to Newton's First Law of Motion, an object moving at a constant velocity has zero acceleration. This means the net force acting on it is zero. Therefore, the applied force pushing the object forward must be equal in magnitude and opposite in direction to the force of kinetic friction resisting the motion.

Question 44: Which fastener type is designed to be installed from one side without access to the back?

Carriage bolt
Hex cap screw
Machine screw
Pop (blind) rivet (Correct answer)

Correct answer: Pop (blind) rivet

Pop rivets (blind rivets) are designed for one-sided installation where the back of the joint is inaccessible.

Question 45: A check valve is installed in a hydraulic line. What does it do?

Regulates flow rate in both directions
Allows fluid to flow in one direction only (Correct answer)
Divides flow equally between two branches
Opens at a set pressure to relieve excess

Correct answer: Allows fluid to flow in one direction only

A check valve contains a ball or poppet that blocks reverse flow while allowing free flow in the intended direction.

Question 46: What does the term 'open circuit' mean?

Current flows freely with no resistance
Voltage is at its maximum
The circuit has too much current
The circuit has a break and no current flows (Correct answer)

Correct answer: The circuit has a break and no current flows

An open circuit is one where the path for current is broken, so no current can flow through it.

Question 47: Which of the following best describes a spring with a high spring constant?

It stretches easily under small loads
It has many active coils
It is made of rubber
It requires large force for small deflection (Correct answer)

Correct answer: It requires large force for small deflection

A high spring constant (k) means the spring is stiff — it resists deformation and requires a large force to stretch or compress it a small amount.

Question 48: Heat flows from a hot object to a cool object. What happens when they reach the same temperature?

Heat flow stops because there is no temperature difference (Correct answer)
Cool object starts sending heat back
Heat continues to flow from hot to cool
Heat reverses direction spontaneously

Correct answer: Heat flow stops because there is no temperature difference

Heat transfer stops when thermal equilibrium is reached—no temperature difference means no net heat flow.

Question 49: An electric motor rated at 1 horsepower (HP) runs continuously. Approximately how many watts does it consume?

1,000 watts
746 watts (Correct answer)
100 watts
350 watts

Correct answer: 746 watts

One mechanical horsepower equals approximately 746 watts, a standard conversion used in motor and engine specifications.

Question 50: A block is pushed against a wall with a horizontal force. What prevents the block from sliding down the wall?

The block's weight
Gravity acting horizontally
Static friction between block and wall (Correct answer)
Normal force from the wall

Correct answer: Static friction between block and wall

The horizontal push creates a normal force against the wall, and static friction acts upward to counterbalance the block's weight.

Question 51: A crane lifts a load on a long boom extended horizontally. As the boom extends farther out, the crane's overall center of gravity:

Moves toward the counterweight side
Stays at the same point regardless of boom extension
Moves toward the load side (Correct answer)
Drops lower to the ground

Correct answer: Moves toward the load side

Extending the boom moves the suspended load farther from the crane's base, shifting the combined center of gravity toward the load side.

Question 52: A coil spring with 20 active coils is replaced by one with 10 active coils (same wire diameter and coil diameter). The new spring is:

Equally stiff
Half as stiff
Four times as stiff
Twice as stiff (Correct answer)

Correct answer: Twice as stiff

Spring constant is inversely proportional to the number of active coils, so halving the coils doubles the stiffness.

Question 53: A heat exchanger transfers heat from hot exhaust gas to cold incoming air. The metal plates between them work because metal:

Radiates heat between the gas streams
Absorbs heat permanently
Has high thermal conductivity, allowing rapid heat transfer through the plates (Correct answer)
Prevents any heat from passing

Correct answer: Has high thermal conductivity, allowing rapid heat transfer through the plates

Metal's high thermal conductivity allows heat to quickly conduct from the hot side through the plate to the cold side.

Question 54: A wheel with a radius of 10 inches is connected by a belt to a wheel with a radius of 5 inches. If the larger wheel rotates at 60 RPM, how fast does the smaller wheel rotate?

240 RPM
60 RPM
30 RPM
120 RPM (Correct answer)

Correct answer: 120 RPM

When connected by a belt, the smaller wheel spins twice as fast because RPM × radius is constant, so 60 × 10/5 = 120 RPM.

Question 55: A wheel rolling uphill loses speed compared to rolling on flat ground (same force applied). This is primarily because:

The wheel diameter increases on hills
The axle friction increases
Gravity adds a resisting force component along the slope (Correct answer)
The wheel circumference decreases

Correct answer: Gravity adds a resisting force component along the slope

On an incline, gravity acts against motion along the slope, requiring additional force to maintain speed, which slows the wheel if force is unchanged.

Question 56: A 200 N force is applied at an angle of 60° above horizontal to push a box across the floor. What is the horizontal component of this force?

100 N (Correct answer)
200 N
173 N
50 N

Correct answer: 100 N

The horizontal component is F × cos(60°) = 200 × 0.5 = 100 N.

Question 57: What happens to system pressure when a hydraulic cylinder reaches the end of its stroke and cannot move further?

Flow increases to compensate
Pressure drops to zero
Pressure stays constant
Pressure rises until the relief valve opens (Correct answer)

Correct answer: Pressure rises until the relief valve opens

With no movement to absorb pump output, pressure builds rapidly until the relief valve opens to protect the system.

Question 58: Gear A (driver, 12 teeth) meshes directly with Gear B (36 teeth). Gear A rotates at 900 RPM. What is Gear B's speed?

2700 RPM
300 RPM (Correct answer)
900 RPM
450 RPM

Correct answer: 300 RPM

Speed of Gear B = (teeth of A / teeth of B) × speed of A = (12/36) × 900 = 300 RPM.

Question 59: What does 'SAE' mean when referring to wrenches and sockets?

Socket and Allen Equipment
Steel Alloy Equipment
Standard Alloy Engineering
Society of Automotive Engineers (inch-based sizing) (Correct answer)

Correct answer: Society of Automotive Engineers (inch-based sizing)

SAE stands for Society of Automotive Engineers, and SAE tools use inch-based measurements (e.g., 1/4", 3/8").

Question 60: In a compound belt drive, power is transmitted through:

A chain and belt combination
A single belt connecting all pulleys at once
Multiple belts connecting intermediate shafts in sequence (Correct answer)
Hydraulic coupling between pulleys

Correct answer: Multiple belts connecting intermediate shafts in sequence

A compound belt drive uses intermediate shafts with multiple pulleys and belts connected in series, allowing large overall speed ratios that a single belt drive could not achieve.

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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