FE / Engineering Mechanics
Cheat sheet by unit
✦ Based on analysis 32 previous papers, here is a breakdown of the trends, question frequency, and strategy for scoring high marks.
1. Distribution Trend by Unit
Maximum marks: 70
| Unit | Hot Topics (Recurring Frequently) | Typical Marks |
|---|---|---|
| Unit I: Resultants, Centroid & MOI | Centroid of shaded areas, moment of inertia of T-section or I-section, and resultant of 3D or space force systems. | 14 |
| Unit II: Equilibrium | Support reactions for beams, and equilibrium of spheres or cylinders in troughs or on inclines. | 14 |
| Unit III: Friction & Trusses | Truss analysis by method of joints or sections, ladder friction, and block-on-incline questions. | 14 |
| Unit IV: Kinematics | Projectile motion, rectilinear motion with s-v-a equations or v-t graphs, and curvilinear motion with n-t components. | 14 |
| Unit V: Kinetics | Work-energy principle for blocks, springs, and pendulums, plus impulse-momentum and impact with coefficient of restitution e. | 14 |
2. Short on Time?
Here is where to start
If you have one week
Study Unit 2 beam reactions, Unit 3 inclined plane and belt friction, and Unit 5 Newton's law and impact. These topics appear in every paper and follow a mechanical procedure every time.
If you have two weeks
Add Unit 4 projectile motion and rectilinear motion, Unit 3 method of joints, and Unit 5 work-energy. You now have coverage for roughly 70% of the marks available.
If you have one day
Open the paper trends page. Read the bang-for-buck table. Solve the recurring problem families listed there. That is the shortest path to marks that exists.
3. Biggest Bang for Buck
High marks vs. low effort
1. Centroid & MOI (Unit I)
These are procedural marks. Once you master the composite-area tabulation method for centroid and the parallel-axis tabulation method for MOI, the questions repeat with only small figure changes.
2. Support Reactions (Unit II)
Beam questions are some of the easiest 5 to 7 marks on the paper. Most of the work is just ΣM = 0 and ΣFᵧ = 0.
3. Projectile Motion (Unit IV)
Most questions reduce to the same two or three kinematic formulas. Getting uₓ and uᵧ right is half the problem.
4. Work-Energy Principle (Unit V)
This is often easier than F = ma because it avoids time and acceleration and stays focused on velocity and position.
4. Easiest Questions
The easy marks
- Theory: law of parallelogram, Varignon’s theorem, and definitions of friction such as angle of repose.
- 2D resultants: straightforward resolution into Fₓ and Fᵧ.
- Equilibrium on smooth surfaces: sphere or cylinder questions where a clean FBD and Lami’s theorem usually carry the answer.
4. Hardest Questions
High risk of errors
- Trusses: one sign error in the first joint can poison the whole solution.
- 3D space forces: these require strong visualization and vector setup with position vector r, force vector F, and direction vector lambda.
- Impact and collision: momentum and energy handling becomes messy when springs or multiple bodies are involved.
- Variable acceleration: when a is given as a function of time, the calculus mistakes start.
5. Summary Advice for Students
To get the highest marks with the least risk, master Unit I for centroid and MOI and Unit II for beams perfectly. These are the easiest marks in the paper. Then pick either work-energy or projectile motion, to lock in your passing marks before you spend too much time on complex trusses.
Unit Cheat Sheets
Open a unit
Unit 1
Force Systems
Resultants, centroids, and moment of inertia. This is the most stable math-first scorer in the subject.
Recurring questions
- - Resultant of concurrent forces using sum F_x and sum F_y.
- - Resultant of parallel or general force systems using moments.
Unit 2
Equilibrium
Beam reactions, free-body diagrams, and classic contact problems. This is the safest high-ROI unit.
Recurring questions
- - Simply supported beam reactions with UDL, UVL, point loads, and moments.
- - Sphere or cylinder equilibrium in a trough or against a wall.
Unit 3
Friction and Trusses
A mixed unit: friction is direction-sensitive, while trusses are method-heavy and repetitive.
Recurring questions
- - Ladder friction and belt friction, especially range-of-P questions.
- - Block or body on an inclined plane with friction.
Unit 4
Kinematics
The motion-description unit. Projectile and rectilinear problems are the safest scorers; variable acceleration is the trap.
Recurring questions
- - Projectile motion with range, maximum height, or time of flight.
- - Rectilinear motion with uniform acceleration and braking distance.
Unit 5
Kinetics
Newton second law, work-energy, and impact. This unit scores well if you pick the right method family for the question.
Recurring questions
- - Newton's 2nd law on blocks, inclines, and connected bodies.
- - Work-energy principle for speed after motion through a distance.