What Is Engineering Mechanics?

Statics, Dynamics, and Mechanics of Materials — three questions about the same physical world.

StaticsMechanical Engineering Year 1Free preview
⏱️ About 12 min

A bridge that doesn't move, a rocket that accelerates, and a beam that bends under load are all governed by the same starting point — Newton's laws — but engineers study each with a different toolkit, and knowing which toolkit to reach for is the first real skill in this course.

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The big idea: Engineering mechanics splits into three linked fields depending on the question you're asking: Statics asks whether something stays still, Dynamics asks how it moves, and Mechanics of Materials asks how it deforms and whether it breaks.
🎯 By the end, you'll be able to
  • Distinguish Statics, Dynamics, and Mechanics of Materials by the question each one answers
  • Explain why this course begins with Statics before Mechanics of Materials
  • Recognize which field a real-world engineering question belongs to

Three questions, one physical world

Statics studies objects that are not accelerating — bridges, buildings, parked cranes, a bookshelf under load. The central question is: what forces must be present to keep this object in equilibrium?

Dynamics studies objects that are accelerating — a car braking, a satellite orbiting, a piston firing. The central question is: given the forces, how does the object move?

Mechanics of Materials (sometimes called Strength of Materials) asks a third, different question: given the forces a structure carries, how much does it deform, and how do we make sure it doesn't break? This is where Statics stops being just about external balance and starts caring about what happens inside the material.

🔑 Why start with Statics?

Mechanics of Materials can't be done without Statics — you can't find the stress inside a beam until you first know the forces acting on it, and finding those forces is exactly what Statics teaches. That's why this course spends its first five modules on Statics before ever mentioning stress or strain.

📝 Worked example: Classify each scenario as primarily Statics, Dynamics, or Mechanics of Materials: (a) finding the tension in a stationary crane cable, (b) finding how fast a falling elevator accelerates before its brake engages, (c) checking whether a loaded shelf bracket will permanently bend.
  1. (a) The crane and cable are not moving — this is a force-balance question about an object at rest, which is Statics.
  2. (b) The elevator is accelerating, so this asks about motion over time — Dynamics.
  3. (c) This asks whether the bracket's material can withstand the load without deforming permanently — Mechanics of Materials.
✓ (a) Statics, (b) Dynamics, (c) Mechanics of Materials.

Check your understanding

1. Which field asks 'what forces keep this object from moving?'
Statics is specifically about objects in equilibrium — not accelerating.
2. Why does this course teach Statics before Mechanics of Materials?
You need to know the forces acting on a structure (Statics) before you can compute the internal stress those forces cause (Mechanics of Materials).
🔎 Related lessons
Vectors & Force Representation
✅ Key takeaways
  • Statics studies objects in equilibrium (not accelerating).
  • Dynamics studies how forces cause motion and acceleration.
  • Mechanics of Materials studies internal deformation and failure, building on the forces found in Statics.
➡️ With the map of the field in hand, the next lesson starts the actual toolkit: representing forces as vectors.
Want to test yourself on this? Try the Mechanical Aptitude test →
🎓 Go deeper: external courses & trusted references

External sites are listed for reference only. This course is independent and has no affiliation with, or endorsement from, the institutions named.