BTEC Engineering Unit 1

What is the formula for calculating force in Newtons?

Force (N) = Mass (kg) × Acceleration (m/s²)

Define "stress" in engineering terms.

Stress is the force applied to a material per unit area. It is measured in Pascals (Pa).

What are the two types of deformation materials can experience?

1. Elastic Deformation: Reversible, returns to original shape when force is removed.
2. Plastic Deformation: Permanent change in shape after force is applied.

What is the difference between a material’s tensile strength and yield strength?

• Tensile Strength: The maximum stress a material can withstand before breaking.

• Yield Strength: The stress at which a material begins to deform plastically.

Define the term “work done” in physics.

Work done is the energy transferred when a force moves an object over a distance.

What is the difference between a vector and a scalar quantity?

• Vector: A quantity that has both magnitude and direction (e.g., force, velocity).

• Scalar: A quantity that has only magnitude, with no direction (e.g., mass, temperature).

What are the four main types of stress-strain behavior?

1. Elastic Region
2. Yield Point
3. Plastic Region
4. Ultimate Strength

What is the difference between a conductor and an insulator?

• Conductor: A material that allows electricity to flow through it easily (e.g., copper).

• Insulator: A material that does not allow electricity to flow through it easily (e.g., rubber).

Define "moment" in engineering.

A moment is the rotational force around a pivot point.

What is the formula for calculating efficiency in a system?

Efficiency (%) = (Useful Power Output / Total Power Input) × 100

Define "Young’s Modulus

Young’s Modulus is a measure of the stiffness of a material, defined as the ratio of stress to strain in the elastic region.

What is the formula for the Moment

Formula: Moment (M) = Force (F) × Distance from Pivot (d)
Unit: Newton-meter (Nm)

What is the formula for young’s modulus

Formula: Young’s Modulus (E) = Stress / Strain

What is the formula for work done

Formula: Work Done (W) = Force (F) × Displacement (s)
Unit: Joules (J)

What is the formula for Direct stress

Formula: Direct Stress (σ) = Force (F) / Area (A)

What is the formula for Direct Strain

Formula: Direct Strain (ε) = Change in Length (ΔL) / Original Length (L)

What is the formula for Shear Stress

Formula: Shear Stress (τ) = Force (F) / Area (A)

What is the formula for Shear Strain

Formula: Shear Strain (γ) = Change in Length (ΔL) / Original Length (L)

what is the formula for the modulus of rigidity

Formula: Modulus of Rigidity (G) = Shear Stress (τ) / Shear Strain (γ)

What is the difference between stress and strain?

• Stress: The force applied per unit area (measured in Pascals).

• Strain: The amount of deformation relative to the original dimensions (a dimensionless quantity).

Define "strain energy."

Strain energy is the energy stored in a material due to deformation under stress.

What is the formula for calculating power?

Power (P) = Work Done (W) / Time (t)
Unit: Watts (W)

What does the term "elastic limit" mean?

The maximum stress a material can endure without undergoing permanent deformation

What is the definition of "tensile strength"?

The maximum stress a material can withstand without breaking when stretched or pulled.

Define "compression" in engineering.

Compression is the force that reduces the volume of a material by squeezing it together.

What are the properties of a material with high ductility?

Materials with high ductility can be stretched or deformed significantly before breaking (e.g., copper, aluminum).

What are the 3 main types of mechanical stress?

1. Tensile Stress
2. Compressive/Direct Stress
3. Shear Stress

Define "shear force."

A force that causes one part of a material to slide or deform relative to another part.

What is the difference between "static" and "dynamic" loads?

• Static Load: A load that is applied gradually and remains constant.

• Dynamic Load: A load that changes over time (e.g., from moving objects).

What is the principle of conservation of energy?

Energy cannot be created or destroyed, only converted from one form to another.

What is a "stress-strain curve"?

A graph showing the relationship between stress and strain for a material.

What is the unit for energy?

The unit for energy is the Joule (J).

What is the difference between "elastic" and "plastic" regions in a stress-strain graph?

• Elastic Region: Where the material returns to its original shape when the stress is removed.

• Plastic Region: Where the material undergoes permanent deformation

What is the definition of "energy efficiency" in a system?

Energy efficiency is the ratio of useful energy output to total energy input, expressed as a percentage.

Define "torsion."

Torsion is the twisting of an object due to an applied torque.

Define Young’s Modulus

• Young’s Modulus is the ratio of tensile stress to tensile strain in the elastic region.

What are the three primary types of stress?

• 1. Tensile Stress
  2. Compressive/Direct Stress
  3. Shear Stress

What is the unit for stress?

The unit for stress is Pascal (Pa) or N/m².

Define "load-bearing capacity."

Load-bearing capacity is the maximum load a structure or material can support without failure.

What is the principle behind "leverage" in engineering?

Leverage refers to the mechanical advantage gained by using a lever, which amplifies force applied to an object.

What is the definition of "shear strain"?

Shear strain is the angular deformation caused when a shear force is applied to a material

What is the purpose of a "bearing" in mechanical systems?

• A bearing is used to reduce friction and allow rotational or linear movement between parts.

Define "resistance" in electrical terms.

Resistance is the opposition to the flow of electric current, measured in ohms (Ω).

What is "ohm's law"?

Ohm’s Law states that the current through a conductor is directly proportional to the voltage and inversely proportional to the resistance.Formula: V = I × R

Define "electrical power" in terms of voltage and current.

Electrical power (P) is the rate at which electrical energy is transferred by an electric circuit.
Formula: P = V × I

What is "alternating current" (AC)?

AC is an electric current that periodically reverses direction, commonly used in power transmission.

What is "direct current" (DC)?

DC is an electric current that flows in one direction only, typically used in batteries and electronic devices.

What is "resistivity"?

Resistivity is a material property that quantifies how strongly a material opposes the flow of electric current. Measured in ohm meters (Ω·m).

What is the formula for calculating electric current?

Current (I) = Voltage (V) / Resistance (R)

Define "fuse" in electrical circuits.

A fuse is a safety device that protects circuits from overcurrent by melting and breaking the circuit when the current exceeds a safe level.

What is the difference between "conductivity" and "resistance"?

• Conductivity is the ability of a material to conduct electricity.

• Resistance is the opposition to the flow of electric current.

What is the formula for calculating electrical energy?

Electrical Energy (E) = Power (P) × Time (t)

What is a "voltage divider" circuit?

A voltage divider is a circuit that uses resistors to create a specific fraction of an input voltage.

What does "electromagnetic induction" refer to?

Electromagnetic induction refers to the generation of an electric current by changing the magnetic field around a conductor.

Define "magnetic field."

• A magnetic field is a region around a magnetic material within which the force of magnetism acts.

What is the function of a "transformer" in electrical systems?

A transformer is a device that changes the voltage level in an alternating current (AC) circuit.

Define "inductance."

Inductance is the property of an electrical circuit that opposes changes in current flow, measured in henries (H).

What is a "capacitor" used for?

A capacitor stores and releases electrical energy in a circuit, often used for smoothing out voltage fluctuations.

What does "impedance" refer to in AC circuits?

Impedance is the total opposition to current flow in an alternating current (AC) circuit, combining resistance and reactance.

Define "resonance" in electrical circuits.

Resonance is the condition in which a circuit’s inductive and capacitive reactance are equal, resulting in maximum current.

What is "reactance" in AC circuits?

• Reactance is the opposition to current flow in an alternating current (AC) circuit caused by inductance or capacitance.

What is "voltage" in electrical terms?

Voltage is the electric potential difference between two points in a circuit, measured in volts (V)

What is the function of a "diode"?

A diode allows current to flow in only one direction, acting as a one-way valve for electric current.

Define "series circuit."

A series circuit is a circuit where components are connected end-to-end, and the same current flows through all components.

Define "parallel circuit."

A parallel circuit is a circuit where components are connected across common points, allowing multiple paths for the current to flow.

What is the "law of conservation of charge"?

• The law states that charge can neither be created nor destroyed; it can only be transferred from one place to another.

What is "voltmeter" used for?

A voltmeter is an instrument used to measure the potential difference (voltage) across two points in a circuit.

What is a "multimeter" used for?

A multimeter is a versatile instrument used to measure voltage, current, and resistance in electrical circuits.

What is the difference between "active" and "passive" electrical components?

• Active components: Components that provide energy to the circuit (e.g., transistors, batteries).

• Passive components: Components that consume or store energy (e.g., resistors, capacitors).

What does "field strength" refer to in electrical terms?

Field strength is the intensity of an electric or magnetic field, measured in volts per meter (V/m) or amperes per meter (A/m).

Define "electromagnetic wave."

An electromagnetic wave is a wave of oscillating electric and magnetic fields that can travel through a vacuum or a medium.

What is "frequency" in terms of electromagnetic waves?

Frequency is the number of cycles of a wave that occur in a unit of time, typically measured in hertz (Hz).

Define "wavelength" in terms of electromagnetic waves.

• Wavelength is the distance between successive peaks or troughs of a wave, typically measured in meters.

What is the difference between "AC" and "DC" in terms of power distribution?

• AC: Alternating current, used for long-distance power transmission.

• DC: Direct current, used in batteries and electronics.

Define "impedance matching."

Impedance matching refers to adjusting the impedance of a load and source to maximize power transfer or minimize signal reflection.