PE Mechanical EXAM QUESTIONS AND CORRECT ANSWERS (VERIFIED ANSWERS) PLUS RATIONALES 2025/2026 Q&A | INSTANT DOWNLOAD PDF

PE Mechanical EXAM QUESTIONS AND
CORRECT ANSWERS (VERIFIED
ANSWERS) PLUS RATIONALES
2025/2026 Q&A | INSTANT DOWNLOAD
PDF

Question 1
The first law of thermodynamics is based on conservation of:
A. Momentum
B. Mass only
C. Energy
D. Entropy
Correct Answer: C
Rationale: The first law states that energy cannot be created or destroyed, only
transferred or converted.


Question 2
The SI unit of power is:
A. Joule
B. Watt
C. Pascal
D. Newton
Correct Answer: B
Rationale: Power is the rate of energy transfer and is measured in watts (J/s).

,Question 3
The SI unit of pressure is:
A. Pascal
B. Watt
C. Kelvin
D. Joule
Correct Answer: A
Rationale: Pressure is measured in pascals, which represent force per unit area.


Question 4
Absolute temperature is measured using:
A. Celsius
B. Fahrenheit
C. Kelvin
D. Rankine only
Correct Answer: C
Rationale: Kelvin is the SI absolute temperature scale beginning at absolute zero.


Question 5
A closed system allows transfer of:
A. Mass only
B. Energy but not mass
C. Mass but not energy
D. Neither mass nor energy
Correct Answer: B

,Rationale: A closed system can exchange energy with its surroundings but does
not exchange mass.


Question 6
An open system allows transfer of:
A. Energy only
B. Mass only
C. Mass and energy
D. Neither mass nor energy
Correct Answer: C
Rationale: Open systems allow both mass and energy to cross their boundaries.


Question 7
The second law of thermodynamics introduces the concept of:
A. Pressure
B. Entropy
C. Velocity
D. Density
Correct Answer: B
Rationale: The second law describes energy quality and introduces entropy as a
measure of disorder.


Question 8
Specific heat is the amount of heat required to raise:
A. One unit of mass by one degree of temperature
B. One object to melting point
C. Pressure by one unit
D. Volume by one unit

, Correct Answer: A
Rationale: Specific heat measures thermal energy required per unit mass per
degree temperature change.


Question 9
The ideal gas law is:
A. PV = mRT
B. F = ma
C. Q = mcΔT
D. W = Pt
Correct Answer: A
Rationale: The ideal gas law relates pressure, volume, temperature, and mass of a
gas.


Question 10
Density is defined as:
A. Mass divided by volume
B. Volume divided by mass
C. Force divided by area
D. Energy divided by time
Correct Answer: A
Rationale: Density equals mass per unit volume.


Question 11
Viscosity measures a fluid’s resistance to:
A. Pressure
B. Flow