What was the hardest class you engineers had to take in college?

Dynamics was a pretty hard class to wrap your brain around. Its' concepts are very 3-dimensional. And there's no easy way to model it. It involved calculating forces, moments, inertia and other things you learned in Statics but the things you are trying to figure out are in motion. But I got through it. Nothing is impossible.

Chemical Engineering Thermodynamics.

Extremely mathematical, and a much more complete treatment than any other discipline gets for an undergraduate degree.

Thermo requires one to develop a new way of looking at things.

Thermodynamics.

Nothing I learned up to that point could prepare me for thermo. I had to learn to think differently. And once I got it, I would get upset at people who don't understand energy.

Dynamics was pretty hard, too.

I found control systems very challenging. Not only did you have to be able to calculate differential equations, everything was theoretical which made it hard to understand.

Calculus 2

Nothing was harder than Calc. 2

Dynamics was hard too

I am a mechanical engineer

mathematics i think. engineering maths can boggle ur mind.