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PE Mechanical Machine Design study materials
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PE Mechanical Machine Design practice questions

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Question 1Basic Engineering Practice

The pascal (Pa) is the SI derived unit of stress. Which combination of base SI units is equivalent to one pascal?

  1. kg·m/s²
  2. N·m
  3. kg/(m·s²) Correct answer.
  4. kg/(m²·s)

Explanation

One pascal is one newton per square metre, and a newton is one kilogram-metre per second squared. Substituting gives kg/(m·s²) as the base-unit form of the pascal.

Question 2Basic Engineering Practice

A drawing dimension is stated as 0.0450 in. How many significant figures does this value carry?

  1. Five
  2. Two
  3. Four
  4. Three Correct answer.

Explanation

Leading zeros used only to position the decimal point are not significant, so the 0 before the decimal and the 0 immediately after it are ignored. The digits 4, 5, and the trailing 0 after the decimal are significant, giving three.

Question 3Basic Engineering Practice

A pressure gauge reads 2.5 MPa. What is this pressure expressed in kilopascals?

  1. 25 kPa
  2. 2 500 kPa Correct answer.
  3. 250 kPa
  4. 25 000 kPa

Explanation

The prefix mega means 10⁶ and kilo means 10³, so one megapascal equals 1000 kilopascals. Multiplying 2.5 by 1000 gives 2500 kPa.

Question 4Basic Engineering Practice

In a third-angle orthographic projection drawing, where is the top view placed relative to the front view?

  1. To the left of the front view
  2. Below the front view
  3. Above the front view Correct answer.
  4. To the right of the front view

Explanation

Third-angle projection places each view on the side of the front view toward which the observer looks, so the top view appears above the front view. First-angle projection, by contrast, places the top view below the front view.

Question 5Basic Engineering Practice

Which hardness test presses a 10 mm hardened ball into the specimen under a 3000 kg load when testing ferrous metals?

  1. Knoop
  2. Brinell Correct answer.
  3. Vickers
  4. Rockwell B

Explanation

The Brinell test uses a 10 mm hardened steel or tungsten carbide ball and a standard 3000 kg load for ferrous metals, reporting a Brinell hardness number from the impression diameter. The other methods use different indenters or load scales.

Question 6Basic Engineering Practice

According to the NSPE Code of Ethics, an engineer's paramount obligation in professional practice is to:

  1. Advance the employer's competitive market position
  2. Hold paramount public health, safety, and welfare Correct answer.
  3. Enhance the reputation of the engineering profession
  4. Protect the client's confidential financial information

Explanation

The first canon of the code requires engineers to hold paramount the safety, health, and welfare of the public. Duties to clients and employers are fulfilled within that overriding obligation.

Question 7Basic Engineering Practice

A steel shaft has a yield strength of 420 MPa and carries a steady bending stress. Using a factor of safety of 3.0 against yielding, what is the maximum allowable stress?

  1. 1260 MPa
  2. 210 MPa
  3. 140 MPa Correct answer.
  4. 420 MPa

Explanation

The allowable stress is the strength divided by the factor of safety, so 420 MPa divided by 3.0 equals 140 MPa. Multiplying by the factor of safety instead of dividing inverts the intent of the design rule.

Question 8Basic Engineering Practice

A journal bearing operates with a complete fluid film that fully separates the shaft from the bearing surface. Which lubrication regime is this?

  1. Boundary
  2. Hydrodynamic Correct answer.
  3. Solid-film
  4. Mixed

Explanation

Hydrodynamic lubrication exists when the converging film generates enough pressure to keep the surfaces completely apart, so no asperity contact occurs. Boundary and mixed regimes involve partial contact between asperities.

Question 9Basic Engineering Practice

In a hole-basis clearance fit, which condition must hold between the hole and shaft limits?

  1. Hole maximum size equals shaft minimum size
  2. The hole and shaft tolerance zones substantially overlap
  3. Shaft minimum size exceeds hole maximum size
  4. Hole minimum size exceeds shaft maximum size Correct answer.

Explanation

A clearance fit guarantees a gap in every permissible assembly, which requires the smallest hole to be larger than the largest shaft. If any overlap of the zones is possible, the fit is transition or interference.

Question 10Basic Engineering Practice

On an engineering drawing, the surface texture parameter Ra represents:

  1. Arithmetic average deviation from the mean line Correct answer.
  2. Average spacing between adjacent profile peaks
  3. Maximum peak-to-valley height across the sampled profile
  4. Ten-point height of the profile irregularities, measured in µm

Explanation

Ra is the arithmetic average of the absolute deviations of the roughness profile from its mean line over the sampling length. Peak-to-valley and ten-point height parameters describe extreme features rather than an average.

Question 11Basic Engineering Practice

A hole of diameter 1.000 ± 0.010 is located by a position tolerance of ⌀0.020 at MMC. If the hole is produced at 1.010, what total position tolerance is permitted?

  1. ⌀0.040 Correct answer.
  2. ⌀0.050
  3. ⌀0.030
  4. ⌀0.020

Explanation

The maximum material condition of the hole is its smallest size, 0.990. The bonus tolerance equals the departure from MMC, 1.010 − 0.990 = 0.020, which is added to the stated ⌀0.020 to give ⌀0.040.

Question 12Basic Engineering Practice

A bolt with a 0.50 in nominal diameter is tightened to a preload of 10,000 lb. Using a nut factor K of 0.20, what tightening torque is required?

  1. 250 ft·lb
  2. 100 ft·lb
  3. 1000 ft·lb
  4. 83 ft·lb Correct answer.

Explanation

The short-form torque relation is T = K·F·d, giving 0.20 × 10,000 lb × 0.50 in = 1000 lb·in. Dividing by 12 converts this to about 83 ft·lb.

Question 13Basic Engineering Practice

A machine costs $50,000 and produces net annual savings of $12,500. What is the simple payback period, ignoring interest?

  1. 4 years Correct answer.
  2. 2 years
  3. 5 years
  4. 3 years

Explanation

Simple payback is the initial cost divided by the annual net cash flow, so $50,000 ÷ $12,500 = 4 years. No discounting is applied in a simple payback calculation.

Question 14Basic Engineering Practice

Which section of the ASME Boiler and Pressure Vessel Code governs the design and fabrication of pressure vessels?

  1. Section VIII Correct answer.
  2. Section IX
  3. Section I
  4. Section II

Explanation

Section VIII contains the rules for construction of pressure vessels, divided into divisions by pressure level and design method. Section I covers power boilers, Section IX covers welding qualification, and Section II covers materials.

Question 15Basic Engineering Practice

In the ISO hole-basis system, the fit designated H7/g6 is best described as:

  1. A force or shrink fit
  2. A transition fit
  3. A close running clearance fit Correct answer.
  4. A locational interference fit

Explanation

A capital H hole with a lower-case g shaft places a small clearance between the limits, producing the close running fit used for journals and sliding parts. Interference and transition fits use shaft letters such as p, n, or k.

Question 16Basic Engineering Practice

A rolling bearing carries the designation 6205. What is its bore diameter?

  1. 25 mm Correct answer.
  2. 20 mm
  3. 62 mm
  4. 5 mm

Explanation

For bore numbers 04 and above, the bore diameter in millimetres equals the last two digits multiplied by 5, so 05 × 5 = 25 mm. The leading digits identify the bearing type and dimension series.

Question 17Basic Engineering Practice

On an AWS welding symbol, where is the size of a fillet weld placed?

  1. To the left of the fillet weld symbol Correct answer.
  2. In the tail of the reference line
  3. Above the reference line
  4. To the right of the fillet weld symbol

Explanation

Standard welding symbology places the weld size immediately to the left of the fillet symbol, while the length and pitch are shown to the right. The tail carries process or specification references.

Question 18Basic Engineering Practice

The material designation ASTM A36 identifies:

  1. A stainless steel containing 36% chromium
  2. Carbon structural steel, 36 ksi minimum yield Correct answer.
  3. A gray cast iron with 36 HRC hardness
  4. An aluminum alloy with 36 ksi tensile strength

Explanation

ASTM A36 is the standard specification for carbon structural steel, and the number 36 refers to the 36 ksi minimum yield strength. It is a plain carbon steel widely used for structural shapes and plate.

Question 19Basic Engineering Practice

An assembly length is made up of four dimensions in series: 1.000 ± 0.002, 0.500 ± 0.003, 0.750 ± 0.001, and 0.250 ± 0.004 in. What is the worst-case variation of the overall length?

  1. 0.005 in
  2. 0.010 in
  3. 0.040 in
  4. 0.020 in Correct answer.

Explanation

In worst-case (arithmetic) tolerancing, the bilateral tolerances add directly: 0.002 + 0.003 + 0.001 + 0.004 = 0.010 in as a plus-or-minus value. The total spread from maximum to minimum length is twice that, or 0.020 in.

Question 20Basic Engineering Practice

In the United States, the term of a utility patent is:

  1. 14 years measured from the date the patent issues
  2. 10 years renewable for a second 10-year term
  3. 20 years from the earliest filing date Correct answer.
  4. 17 years measured from the date the patent issues

Explanation

Utility patents granted on or after June 8, 1995 run for 20 years measured from the earliest effective non-provisional filing date, subject to maintenance fees and any patent term adjustment. The older 17-year-from-issue term no longer applies.

Question 21Basic Engineering Practice

Four independent dimensions with tolerances of 0.004, 0.006, 0.002, and 0.008 in are stacked in series. Using the statistical (root-sum-square) method, what is the combined tolerance?

  1. 0.011 in Correct answer.
  2. 0.005 in
  3. 0.015 in
  4. 0.020 in

Explanation

The root-sum-square combination is the square root of the sum of the squares: √(0.004² + 0.006² + 0.002² + 0.008²) = √0.000120 ≈ 0.011 in. This is smaller than the 0.020 in arithmetic worst-case stack.

Question 22Basic Engineering Practice

A steel shaft of 100.000 mm diameter is to be assembled into an aluminum hub whose bore is 99.950 mm at 20 °C. Using α = 23 × 10⁻⁶ per °C for aluminum, approximately how much must the hub be heated to provide 0.010 mm of diametral clearance?

  1. 52 °C
  2. 13 °C
  3. 65 °C
  4. 26 °C Correct answer.

Explanation

The bore must grow by the 0.050 mm interference plus 0.010 mm clearance, or 0.060 mm. Diametral growth is α·d·ΔT, so ΔT = 0.060/(23 × 10⁻⁶ × 99.95) ≈ 26 °C above ambient.

Question 23Basic Engineering Practice

A hole is specified as 25.000/25.021 mm and its mating shaft as 24.980/24.993 mm. What is the maximum diametral clearance of this fit?

  1. 0.028 mm
  2. 0.007 mm
  3. 0.021 mm
  4. 0.041 mm Correct answer.

Explanation

Maximum clearance occurs with the largest hole paired with the smallest shaft: 25.021 − 24.980 = 0.041 mm. Minimum clearance would be 25.000 − 24.993 = 0.007 mm.

Question 24Basic Engineering Practice

A datum feature of size is referenced at MMB in a feature control frame. What effect does this have on the positional tolerance of the controlled feature?

  1. It removes any bonus tolerance from the positional callout
  2. It allows datum shift that can increase the tolerance Correct answer.
  3. It requires the datum feature to be produced at MMC size
  4. It converts the position tolerance to a profile tolerance

Explanation

Referencing a datum feature of size at MMB establishes a fixed datum simulator at the virtual condition boundary, so a datum feature produced away from MMB may shift within that boundary. The resulting datum feature shift can add to the permissible location error, effectively increasing the available tolerance.

Question 25Basic Engineering Practice

A $10,000 machine is expected to return $2,000 per year for 8 years. With a minimum attractive rate of return of 10% per year, what is the net present worth and the correct decision?

  1. +$2,000; accept the investment
  2. −$670; reject the investment
  3. $0; the investment is marginal
  4. +$670; accept the investment Correct answer.

Explanation

The present worth factor for 8 years at 10% is (P/A) = 5.3349, so the present worth of the savings is $2,000 × 5.3349 = $10,670. Subtracting the $10,000 first cost gives a net present worth of about +$670, so the investment meets the 10% criterion.

Question 26Basic Engineering Practice

An engineer evaluating vendor proposals is offered an all-expenses-paid vacation by one vendor. According to the NSPE Code of Ethics, the engineer should:

  1. Accept it if the vendor is a preferred supplier
  2. Decline the gift and report it to the employer Correct answer.
  3. Accept it but record it in the project file
  4. Accept it because gifts are common industry practice

Explanation

Engineers must avoid conflicts of interest and the appearance of impropriety; a valuable personal gift from a vendor can improperly influence selection. The offer should be declined and disclosed to the employer so the organization can manage the conflict.

Question 27Basic Engineering Practice

The pascal (Pa), the SI unit of pressure and stress, is equivalent to:

  1. 1 kg/m³
  2. 1 J/s
  3. 1 N/m² Correct answer.
  4. 1 N·m

Explanation

Pressure is force per unit area, so one pascal equals one newton per square meter. The other combinations correspond to torque or energy, density, and power.

Question 28Basic Engineering Practice

On an engineering drawing, a hidden edge is conventionally shown with which line type?

  1. Break line
  2. Phantom line
  3. Dashed line Correct answer.
  4. Chain line

Explanation

Hidden edges are drawn with short dashes so they can be distinguished from visible object lines. Chain lines mark centerlines, phantom lines show alternate positions, and break lines indicate omitted sections.

Question 29Basic Engineering Practice

A factor of safety for a machine component is defined as the ratio of:

  1. Allowable stress divided by yield strength
  2. Ultimate strength divided by working stress
  3. Strength divided by allowable stress Correct answer.
  4. Working stress divided by yield strength

Explanation

Factor of safety compares the material strength (yield, ultimate, or fatigue limit) with the allowable or working stress. A value greater than one provides margin against failure.

Question 30Basic Engineering Practice

In a shaft-basis limit system, the fundamental deviation is applied to which feature?

  1. Neither the shaft nor hole
  2. The shaft Correct answer.
  3. The hole
  4. Both the shaft and hole

Explanation

In a shaft-basis system the shaft limits are fixed relative to nominal size, and different hole deviations produce the required fit. A hole-basis system instead fixes the hole limits.

Question 31Basic Engineering Practice

A flatness tolerance is specified for a machined surface. How many datum references does a flatness control require?

  1. One secondary datum
  2. Two datum references
  3. No datum reference Correct answer.
  4. One primary datum

Explanation

Flatness is a form tolerance that controls a surface without relating it to any other feature, so no datum reference is used. Orientation and location tolerances, by contrast, require datums.

Question 32Basic Engineering Practice

A project requires an initial investment of $20,000 and returns $5,000 per year for 6 years with no salvage value. At an interest rate of 8% per year, the present worth is closest to:

  1. $1,900
  2. $4,600
  3. $3,100 Correct answer.
  4. $2,400

Explanation

The present worth factor for 6 years at 8% is about 4.623, so the benefits are worth 5,000 × 4.623 = $23,115. Subtracting the $20,000 initial cost gives about $3,100.

Question 33Basic Engineering Practice

Which type of U.S. patent protects the ornamental appearance of a manufactured article?

  1. Provisional patent
  2. Utility patent
  3. Plant patent
  4. Design patent Correct answer.

Explanation

A design patent covers the ornamental design or appearance of an article. Utility patents protect how an invention works or is used, and plant patents cover new plant varieties.

Question 34Basic Engineering Practice

On an AWS welding symbol, what is the purpose of the tail?

  1. Name the reference specification Correct answer.
  2. Locate the arrow side
  3. Show the groove angle
  4. Indicate the weld size

Explanation

The tail of a welding symbol is used to reference a specification, process, or other instruction. Weld size, groove angle, and arrow-side location are shown elsewhere on the symbol.

Question 35Basic Engineering Practice

A ball bearing has a basic dynamic load rating of 10 kN and operates under an equivalent load of 2 kN. Its basic rating life is closest to:

  1. 1,000 million revolutions
  2. 500 million revolutions
  3. 25 million revolutions
  4. 125 million revolutions Correct answer.

Explanation

For ball bearings the basic rating life is L10 = (C/P)^3 million revolutions. With C/P = 5, L10 = 5^3 = 125 million revolutions.

Question 36Basic Engineering Practice

Five dimensions in series have bilateral tolerances of ±0.002, ±0.003, ±0.001, ±0.004, and ±0.002 in. What is the worst-case resultant bilateral tolerance?

  1. ±0.024 in
  2. ±0.012 in Correct answer.
  3. ±0.006 in
  4. ±0.008 in

Explanation

In worst-case tolerance analysis, the half-widths add directly: 0.002 + 0.003 + 0.001 + 0.004 + 0.002 = 0.012 in. The resultant dimension therefore has a bilateral tolerance of ±0.012 in.

Question 37Basic Engineering Practice

The SAE designation 4140 identifies a steel that is primarily alloyed with:

  1. Carbon only
  2. Chromium and vanadium
  3. Chromium and molybdenum Correct answer.
  4. Nickel and chromium

Explanation

In the SAE/AISI numbering system, the 41xx series denotes chromium-molybdenum steels. The 13xx, 43xx, and 61xx series indicate manganese, nickel-chromium, and chromium-vanadium steels, respectively.

Question 38Basic Engineering Practice

A thin-walled cylindrical pressure vessel has an internal diameter of 1.0 m and a design pressure of 2.0 MPa. The allowable hoop stress is 150 MPa and the joint efficiency is 1.0. The minimum wall thickness is closest to:

  1. 6.7 mm Correct answer.
  2. 13.3 mm
  3. 1.7 mm
  4. 3.3 mm

Explanation

For a thin-walled cylinder, hoop stress is σ = pD/(2t), so t = pD/(2σ). Substituting p = 2.0 MPa, D = 1000 mm, and σ = 150 MPa gives t = (2.0)(1000)/(2 × 150) = 6.7 mm.

Question 39Basic Engineering Practice

Five independent dimensions in series have tolerances of ±0.003, ±0.005, ±0.002, ±0.004, and ±0.001 in. Using root-sum-square analysis, the resultant bilateral tolerance is closest to:

  1. ±0.0074 in Correct answer.
  2. ±0.0100 in
  3. ±0.0150 in
  4. ±0.0050 in

Explanation

The root-sum-square half-width is the square root of the sum of the squares: √(0.003² + 0.005² + 0.002² + 0.004² + 0.001²) = √0.000055 ≈ 0.0074 in. The resultant tolerance is therefore about ±0.0074 in.

Question 40Basic Engineering Practice

A shoulder in a steel bar has a theoretical stress concentration factor of 2.5. If the notch sensitivity is 0.8, the fatigue notch factor is:

  1. 2.5
  2. 2.2 Correct answer.
  3. 1.8
  4. 2.0

Explanation

The fatigue notch factor is Kf = 1 + q(Kt − 1), where q is the notch sensitivity. Thus Kf = 1 + 0.8(2.5 − 1) = 2.2.

Question 41Basic Engineering Practice

A 1/2-13 UNC SAE grade 5 bolt has a tensile stress area of 0.1419 in² and a proof strength of 85 ksi. Its maximum proof load is closest to:

  1. 10,000 lb
  2. 8,000 lb
  3. 15,000 lb
  4. 12,100 lb Correct answer.

Explanation

Proof load equals proof strength times tensile stress area: 85,000 psi × 0.1419 in² ≈ 12,060 lb. This is the load the bolt can sustain without permanent set.

Question 42Basic Engineering Practice

Poisson's ratio for an isotropic material is best described as:

  1. A dimensionless ratio of lateral to axial strain Correct answer.
  2. A measure of surface hardness
  3. A value measured in pascals
  4. A value equal to the elastic modulus

Explanation

Poisson's ratio is the negative ratio of transverse strain to axial strain in uniaxial loading. Being a ratio of strains, it is dimensionless and typically ranges from about 0.2 to 0.5 for engineering materials.

Question 43Basic Engineering Practice

Which organization publishes the ASME Y14.5 standard for dimensioning and tolerancing?

  1. ISO
  2. SAE
  3. AWS
  4. ASME Correct answer.

Explanation

ASME Y14.5 is published by the American Society of Mechanical Engineers and defines dimensioning and tolerancing practices. ISO, AWS, and SAE publish other standards in their respective fields.

Question 44Basic Engineering Practice

In a typical engineering drawing title block, the abbreviation MATL indicates:

  1. Machining tolerance
  2. Material Correct answer.
  3. Manufacturing allowance
  4. Minimum allowance

Explanation

MATL is a standard abbreviation for material in a title block, often followed by the material specification. The other terms are not represented by that abbreviation.

Question 45Basic Engineering Practice

A hole-basis fit designated 50 H7/js6 is best classified as:

  1. Clearance fit
  2. Interference fit
  3. Transition fit Correct answer.
  4. Line fit

Explanation

In the H7/js6 fit, the shaft limits straddle the hole limits, so either a small clearance or a small interference may result. Such a fit is called a transition fit.

Question 46Basic Engineering Practice

Which U.S. regulation establishes requirements for machine guarding of rotating shafts and other hazardous machine parts?

  1. ASME B31.3
  2. OSHA 1910.212 Correct answer.
  3. ISO 9001
  4. NFPA 70

Explanation

OSHA 29 CFR 1910.212 is the general industry standard for machine guarding. ASME B31.3 covers piping, NFPA 70 is the electrical code, and ISO 9001 addresses quality management.

Question 47Basic Engineering Practice

A thread callout of 1/4-20 UNC indicates that the thread has:

  1. 20 threads per inch Correct answer.
  2. A 20 mm pitch
  3. A 0.20 in major diameter
  4. A grade 20 strength

Explanation

In unified thread callouts, the number after the nominal diameter is the number of threads per inch. Thus 1/4-20 UNC has 20 threads per inch and a 1/4 in nominal major diameter.

Question 48Basic Engineering Practice

Which heat treatment is used primarily to relieve residual stresses in a weldment without substantially changing its hardness?

  1. Quenching
  2. Austenitizing
  3. Stress relieving Correct answer.
  4. Case hardening

Explanation

Stress relieving heats the part to a temperature below the critical range and cools it slowly, allowing residual stresses to relax. Quenching, austenitizing, and case hardening intentionally alter microstructure or hardness.

Question 49Basic Engineering Practice

On an engineering drawing, the abbreviation TYP means:

  1. Tolerance
  2. Taper
  3. Typical Correct answer.
  4. Tangent

Explanation

TYP is an abbreviation for typical and indicates that a dimension or feature applies to similar items. It does not denote tolerance, taper, or tangent.

Question 50Basic Engineering Practice

A machine costs $40,000 and has an estimated salvage value of $4,000 after 5 years. Using straight-line depreciation, the annual depreciation charge is:

  1. $6,400
  2. $8,000
  3. $7,200 Correct answer.
  4. $9,000

Explanation

Straight-line depreciation is (initial cost − salvage value)/life. Here ($40,000 − $4,000)/5 = $7,200 per year.