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OpenStem
@openstem · Joined Jul 2026
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Flashcards6 cards
AND gate: A = 1, B = 1. What is the output?1 / 6
1 — both inputs are 1, so the AND gate outputs 1.
Engineering · L3 · Digital Logic Gates — Truth Table Practice
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Engineering · L3 · Digital Logic Gates — Truth Table PracticeFlashcards8 cards
What is specific heat capacity?1 / 8
The amount of heat energy needed to raise the temperature of 1 kg of a material by 1 °C (or 1 K). It's a property of the material — a way of measuring how much energy it takes to warm something up.
Engineering · L3 · Specific Heat Capacity
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Engineering · L3 · Specific Heat CapacityFlashcards6 cards
How much heat is released when 3 kg of aluminum (c ≈ 900 J/(kg·°C)) cools from 150 °C to 30 °C?1 / 6
ΔT = 120 °C. Q = m·c·ΔT = 3 × 900 × 120 = 324,000 J = 324 kJ released.
Engineering · L3 · Specific Heat Capacity
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Engineering · L3 · Specific Heat CapacityFlashcards10 cards
State Archimedes' principle and its formula.1 / 10
The buoyant force on an object in a fluid equals the weight of the fluid the object displaces:
Engineering · L3 · Buoyancy & Archimedes' Principle
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Engineering · L3 · Buoyancy & Archimedes' PrincipleFlashcards10 cards
What is the first step in the engineering design process, before any sketching begins?1 / 10
Define the problem and requirements. For the phone stand: it must hold a phone upright at a comfortable viewing angle, on a desk, without tipping over, and it should be cheap and quick to build from materials on hand.
Engineering · L3 · Design Process Case Study
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Engineering · L3 · Design Process Case StudyFlashcards9 cards
What is materials cost, in a project budget?1 / 9
The total amount spent on physical materials — found by multiplying the quantity of each material needed by its unit price, then summing over every material in the project.
Engineering · L3 · Cost Estimation & Budgeting
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Engineering · L3 · Cost Estimation & BudgetingFlashcards8 cards
A fence needs 40 meters of wire at $3 per meter, plus $150 for labor. What is the total cost?1 / 8
Materials cost = 40 × $3 = $120. Total cost = $120 + $150 = $270.
Engineering · L3 · Cost Estimation & Budgeting
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Engineering · L3 · Cost Estimation & BudgetingFlashcards11 cards
What is direct shear stress, and what is its formula?1 / 11
The internal stress that develops when a force acts parallel (tangential) to a cross-section, tending to slide one part of the material past the other:
Engineering · L3 · Shear Stress
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Engineering · L3 · Shear StressFlashcards9 cards
A 10 mm-diameter bolt carries 5000 N in single shear. Find the shear stress.1 / 9
A = π(0.005)² ≈ 7.854 × 10⁻⁵ m². τ = F/A = 5000 / 7.854 × 10⁻⁵ ≈
Engineering · L3 · Shear Stress
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Engineering · L3 · Shear StressFlashcards11 cards
What is buckling, in a structural column?1 / 11
A sudden sideways bowing failure of a slender member under a compressive (squeezing) load — the column snaps sideways well before the material itself would crush or yield.
Engineering · L3 · Column Buckling
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Engineering · L3 · Column BucklingFlashcards8 cards
A pinned-pinned steel column has E = 200 GPa, I = 8 × 10⁻⁶ m⁴, and L = 3 m. What is its critical buckling load?1 / 8
Engineering · L3 · Column Buckling
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Engineering · L3 · Column BucklingFlashcards11 cards
What is the basic difference between AC and DC?1 / 11
DC (direct current) flows in one constant direction — its voltage and current don't change sign. AC (alternating current) periodically reverses direction, with its voltage swinging positive and negative in a repeating cycle, usually a sine wave.
Engineering · L3 · AC Circuits — Concepts
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Engineering · L3 · AC Circuits — ConceptsFlashcards10 cards
US household power is 120 V RMS. What is the peak voltage?1 / 10
V_peak = V_rms × √2 = 120 × 1.414 ≈ 169.7 V.
Engineering · L3 · AC Circuits — Numeric Problems
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Engineering · L3 · AC Circuits — Numeric ProblemsFlashcards9 cards
What is a transistor, in the simplest sense?1 / 9
An electrically-controlled switch. A small control current or voltage at one terminal lets it switch a much larger current on or off at the other two terminals — with no moving parts.
Engineering · L3 · Transistors as Switches
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Engineering · L3 · Transistors as SwitchesFlashcards8 cards
A microcontroller output pin can only supply about 4 mA, but a small motor needs 150 mA to run. How does a transistor solve this?1 / 8
Wire the pin to the transistor's base (through a resistor). The small 4 mA base current switches the much larger 150 mA collector current, which powers the motor from a separate supply — the microcontroller pin never has to carry the motor's current itself.
Engineering · L3 · Transistor Switching — Applications & Practice
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Engineering · L3 · Transistor Switching — Applications & PracticeFlashcards9 cards
What is viscosity?1 / 9
A fluid's internal resistance to flow — how much it resists being deformed or sheared as it moves. A high-viscosity fluid like honey resists flowing much more than a low-viscosity fluid like water, which pours and splashes freely.
Engineering · L3 · Viscosity & Flow Regimes
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Engineering · L3 · Viscosity & Flow RegimesFlashcards9 cards
Why does pushing fluid through a pipe in turbulent flow take more pumping energy than laminar flow, at the same flow rate?1 / 9
Turbulent eddies constantly churn and mix the fluid, converting useful kinetic energy into heat through internal friction. That extra energy loss has to be made up somewhere, so a pump has to supply more pressure to push the same flow rate through a turbulent pipe than a laminar one.
Engineering · L3 · Viscosity in Engineering Practice
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Engineering · L3 · Viscosity in Engineering PracticeFlashcards9 cards
What is a heat exchanger?1 / 9
A device that transfers heat from one fluid stream to another without letting the two fluids physically mix — they stay separated by a thin metal wall or set of tubes that heat can conduct through.
Engineering · L3 · Heat Exchangers
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Engineering · L3 · Heat ExchangersFlashcards9 cards
What is a parallel-flow heat exchanger?1 / 9
An arrangement where both fluids enter at the same end and travel through the exchanger in the same direction, exiting at the same end.
Engineering · L3 · Heat Exchangers
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Engineering · L3 · Heat ExchangersFlashcards10 cards
What is FMEA?1 / 10
Failure Mode and Effects Analysis — a systematic method engineers use to find and rank the ways a product or process could fail, before it ships, so the highest-risk problems get fixed first instead of being discovered by customers.
Engineering · L3 · Failure Mode and Effects Analysis
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Engineering · L3 · Failure Mode and Effects AnalysisFlashcards8 cards
A failure mode is rated Severity 7, Occurrence 4, Detection 5. What is its RPN?1 / 8
RPN = 7 × 4 × 5 = 140.
Engineering · L3 · Failure Mode and Effects Analysis
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Engineering · L3 · Failure Mode and Effects AnalysisFlashcards10 cards
What is a professional code of ethics, in the context of engineering?1 / 10
A set of principles that an engineering professional body asks its members to follow — covering things like honesty, competence, and (almost always ranked first) protecting public safety, health, and welfare above every other consideration.
Engineering · L3 · Professional Responsibility
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Engineering · L3 · Professional ResponsibilityFlashcards8 cards
An engineer finds a wiring flaw in a product two days before it ships. Fixing it means missing the launch date. What's the ethically correct first move?1 / 8
Report the flaw and its safety implications to the appropriate people immediately — don't decide alone to stay silent to protect the launch date. The team may still find a fix in time, or may decide to delay; either way, the decision needs to be made with the safety information on the table, not hidden.
Engineering · L3 · Ethics — Scenario Practice
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Engineering · L3 · Ethics — Scenario PracticeFlashcards10 cards
What is fatigue, in an engineering context?1 / 10
Progressive, localized damage that builds up in a material from repeated cyclic loading and unloading — damage that can eventually cause failure at a stress level far below the material's static yield strength, even though no single load cycle comes close to overloading it.
Engineering · L3 · Fatigue & Cyclic Loading
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Engineering · L3 · Fatigue & Cyclic LoadingFlashcards9 cards
Why might a fatigue fracture surface look different from a fracture surface caused by a single static overload?1 / 9
A fatigue surface often shows smooth, curved "beach marks" (striations) left behind by the slow crack-propagation stage, next to a rougher, more jagged patch where the final, sudden fracture happened. A static overload fracture, by contrast, tends to look uniformly rough or torn across the whole surface, since it all failed at once with no slow-growth stage.
Engineering · L3 · Fatigue & Cyclic Loading
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Engineering · L3 · Fatigue & Cyclic LoadingFlashcards9 cards
What is specific strength, also called the strength-to-weight ratio?1 / 9
A material's strength (often its yield stress) divided by its density. It tells you how much load-carrying capability you get for every kilogram of material — not just how strong the material is outright.
Engineering · L3 · Specific Strength Concepts
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Engineering · L3 · Specific Strength ConceptsFlashcards9 cards
A material has a yield strength of 300 MPa and a density of 3.0 g/cm³. What is its specific strength?1 / 9
Specific strength = 300 ÷ 3.0 = 100 (MPa per g/cm³).
Engineering · L3 · Specific Strength Numeric Problems
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Engineering · L3 · Specific Strength Numeric ProblemsFlashcards10 cards
What is a voltage divider?1 / 10
Two resistors connected in series across a voltage supply. The output voltage, tapped from the junction between them, is a fraction of the supply voltage set by the resistor ratio.
Engineering · L3 · Voltage Dividers — Concepts
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Engineering · L3 · Voltage Dividers — ConceptsFlashcards10 cards
Vin = 9 V, R1 = 1 kΩ, R2 = 2 kΩ. Find Vout.1 / 10
Vout = 9 × 2000/(1000+2000) = 9 × 2/3 ≈ 6 V.
Engineering · L3 · Voltage Dividers — Worked Problems
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Engineering · L3 · Voltage Dividers — Worked ProblemsFlashcards9 cards
How do you find the equivalent resistance of resistors connected in series?1 / 9
Req = R1 + R2 + R3 + ... — just add up every resistance in the chain.
Engineering · L3 · Series Resistor Networks
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Engineering · L3 · Series Resistor Networks