Where can I find the PE — Mechanical PE — Mechanical question paper 2025?

The full PE — Mechanical PE — Mechanical 2025 (Model questions) question paper is available free on Kekkei. You can read every question online and attempt the paper under timed exam conditions.

Does the PE — Mechanical 2025 paper come with solutions?

Yes. Every question on this PE — Mechanical past paper includes a step-by-step solution, plus instant AI feedback when you attempt it on Kekkei.

How many marks is the PE — Mechanical PE — Mechanical 2025 paper?

The PE — Mechanical PE — Mechanical 2025 paper carries 80 full marks and is meant to be completed in 480 minutes, across 10 questions.

Is practising this PE — Mechanical past paper free?

Yes — reading and attempting this PE — Mechanical past paper on Kekkei is completely free.

PE — Mechanical PE — Mechanical Practice Test 2025

PE — MechanicalModel questions

80marks

480min

10questions

This is the official PE — Mechanical PE — Mechanical question paper for 2025, as set in the Model questions examination. It carries 80 full marks and a time allowance of 480 minutes, across 10 questions. On Kekkei you can attempt this PE — Mechanical past paper online with a timer, get instant AI feedback and step-by-step solutions, and track the topics where you lose marks — completely free. Whether you are revising for your PE — Mechanical PE — Mechanical exam or solving previous years' question papers, this 2025 paper is a great way to practise under real exam conditions.

Level	PE — Mechanical
Subject	PE — Mechanical
Year	2025 BS
Exam session	Model questions
Full marks	80
Time allowed	480 minutes
Questions	10, all with step-by-step solutions

Mechanical Engineering

Select the best answer.

10 questions·1 mark each

1Multiple choice1 mark

AC system: $Q_s = 15\,\text{kW}$ , $T_s = 14^\circ\text{C}$ , $T_r = 24^\circ\text{C}$ , $c_p = 1.005\,\text{kJ/(kg\cdot K)}$ :

\dot{m} = \frac{Q_s}{c_p(T_r - T_s)}

a
$0.75\,\text{kg/s}$
b
$1.49\,\text{kg/s}$
c
$2.24\,\text{kg/s}$
d
$3.00\,\text{kg/s}$

Correct answer: b

$1.49\,\text{kg/s}$

\dot{m} = \frac{15}{1.005 \times 10} = 1.49\,\text{kg/s}

hvac

2Multiple choice1 mark

Counterflow HX: $T_{h,in}=150^\circ$ , $T_{h,out}=90^\circ$ , $T_{c,in}=30^\circ$ , $T_{c,out}=80^\circ$ . LMTD:

\Delta T_{lm} = \frac{\Delta T_1 - \Delta T_2}{\ln(\Delta T_1/\Delta T_2)}

a
$48.1^\circ\text{C}$
b
$55.5^\circ\text{C}$
c
$64.9^\circ\text{C}$
d
$70.0^\circ\text{C}$

Correct answer: c

$64.9^\circ\text{C}$

\Delta T_1 = 70^\circ,\ \Delta T_2 = 60^\circ

\Delta T_{lm} = \frac{10}{\ln(70/60)} = \frac{10}{0.1542} = 64.9^\circ\text{C}

thermal-systems

3Multiple choice1 mark

Shaft: $M = 500\,\text{N\cdot m}$ , $T = 400\,\text{N\cdot m}$ . Equivalent torque (max shear stress theory):

T_e = \sqrt{M^2 + T^2}

a
$500\,\text{N\cdot m}$
b
$640\,\text{N\cdot m}$
c
$750\,\text{N\cdot m}$
d
$900\,\text{N\cdot m}$

Correct answer: b

$640\,\text{N\cdot m}$

T_e = \sqrt{250{,}000 + 160{,}000} = \sqrt{410{,}000} = 640\,\text{N\cdot m}

machine-design

4Multiple choice1 mark

Spring-mass system: $m = 5\,\text{kg}$ , $k = 2{,}000\,\text{N/m}$ . Natural frequency:

f_n = \frac{1}{2\pi}\sqrt{k/m}

a
$2.01\,\text{Hz}$
b
$3.18\,\text{Hz}$
c
$4.50\,\text{Hz}$
d
$6.37\,\text{Hz}$

Correct answer: b

$3.18\,\text{Hz}$

f_n = \frac{1}{2\pi}\sqrt{400} = \frac{20}{6.283} = 3.18\,\text{Hz}

vibration

5Multiple choice1 mark

Centrifugal pump: $Q = 0.05\,\text{m}^3/\text{s}$ , $H = 30\,\text{m}$ , $\gamma = 9{,}810\,\text{N/m}^3$ :

P_w = \gamma Q H

a
$7.36\,\text{kW}$
b
$14.72\,\text{kW}$
c
$22.07\,\text{kW}$
d
$29.43\,\text{kW}$

Correct answer: b

$14.72\,\text{kW}$

P_w = 9810 \times 0.05 \times 30 = 14{,}715\,\text{W} = 14.72\,\text{kW}

fluid-systems

6Multiple choice1 mark

Thin-walled cylinder: $r = 0.5\,\text{m}$ , $t = 10\,\text{mm}$ , $p = 2\,\text{MPa}$ . Hoop stress:

\sigma_h = \frac{pr}{t}

a
$50\,\text{MPa}$
b
$100\,\text{MPa}$
c
$150\,\text{MPa}$
d
$200\,\text{MPa}$

Correct answer: b

$100\,\text{MPa}$

\sigma_h = \frac{2 \times 500}{10} = 100\,\text{MPa}

Hoop stress is twice the longitudinal stress.

pressure-vessels

7Multiple choice1 mark

Cooling tower: $\dot{m}_w = 50\,\text{kg/s}$ , $\Delta T = 10^\circ\text{C}$ , $c_p = 4.18\,\text{kJ/(kg\cdot K)}$ :

\dot{Q} = \dot{m}_w c_p \Delta T

a
$1{,}045\,\text{kW}$
b
$2{,}090\,\text{kW}$
c
$3{,}135\,\text{kW}$
d
$4{,}180\,\text{kW}$

Correct answer: b

$2{,}090\,\text{kW}$

\dot{Q} = 50 \times 4.18 \times 10 = 2{,}090\,\text{kW}

hvac

8Multiple choice1 mark

Rankine cycle: turbine work $w_t = 1{,}200\,\text{kJ/kg}$ , pump work $w_p = 10\,\text{kJ/kg}$ . Net work:

a
$1{,}190\,\text{kJ/kg}$
b
$1{,}200\,\text{kJ/kg}$
c
$1{,}210\,\text{kJ/kg}$
d
$1{,}100\,\text{kJ/kg}$

Correct answer: a

$1{,}190\,\text{kJ/kg}$

w_{net} = w_t - w_p = 1200 - 10 = 1{,}190\,\text{kJ/kg}

thermal-systems

9Multiple choice1 mark

Bolt: $S_p = 600\,\text{MPa}$ , $A_t = 150\,\text{mm}^2$ . Preload at 75% proof:

F_i = 0.75 \cdot S_p \cdot A_t

a
$45.0\,\text{kN}$
b
$67.5\,\text{kN}$
c
$90.0\,\text{kN}$
d
$112.5\,\text{kN}$

Correct answer: b

$67.5\,\text{kN}$

F_i = 0.75 \times 600 \times 150 = 67{,}500\,\text{N} = 67.5\,\text{kN}

machine-design

10Multiple choice1 mark

Shaft critical speed $N_{cr} = 3{,}000\,\text{rpm}$ . Safe range above critical starts at $1.3 N_{cr}$ :

a
$3{,}000\,\text{rpm}$
b
$3{,}600\,\text{rpm}$
c
$3{,}900\,\text{rpm}$
d
$4{,}500\,\text{rpm}$

Correct answer: c

$3{,}900\,\text{rpm}$

1.3 \times 3{,}000 = 3{,}900\,\text{rpm}

Avoid operating between $2{,}100$ and $3{,}900\,\text{rpm}$ .

vibration

Frequently asked questions

Where can I find the PE — Mechanical PE — Mechanical question paper 2025?: The full PE — Mechanical PE — Mechanical 2025 (Model questions) question paper is available free on Kekkei. You can read every question online and attempt the paper under timed exam conditions.
Does the PE — Mechanical 2025 paper come with solutions?: Yes. Every question on this PE — Mechanical past paper includes a step-by-step solution, plus instant AI feedback when you attempt it on Kekkei.
How many marks is the PE — Mechanical PE — Mechanical 2025 paper?: The PE — Mechanical PE — Mechanical 2025 paper carries 80 full marks and is meant to be completed in 480 minutes, across 10 questions.
Is practising this PE — Mechanical past paper free?: Yes — reading and attempting this PE — Mechanical past paper on Kekkei is completely free.