How a Physics Class changed the way I See Things

Victor M. Estremera 

I’ve always been curious to know how things are made or how they work, which is why I decided to study Mechanical Engineering. When I started College, I was looking forward to my Major Courses, but wasn’t too thrilled about Physics I & II because I couldn’t find a relation between Physics and Engineering.

As much as I enjoyed watching TV shows that explain how machines and Manufacturing Plants operate from an Engineering point of view, I couldn’t understand why Physics I & II were so important in my curriculum. It wasn’t until I started taking Major Courses such as Thermodynamics, Electric Circuits and Fluid Mechanics that I understood how Physics is associated with Engineering. Physics is the base to Engineering, regardless of the Engineering Specialization.

For example, Civil Engineers couldn’t design a bridge without understanding Newton’s Laws of Motion from Physics I. The Second Law states that F = ma. The Third Law states that the mutual forces of action and reaction between two bodies are equal and opposite. That’s why in Statics, combining these two laws, the sum of the forces acting on the bridge must be zero in order to stay fixed. Chemical Engineers wouldn’t be able to solve problems of Physical Chemistry and Thermodynamics without understanding topics from Physics I such as the Ideal Gas Law or The Kinetic Theory of Gases. 

Electrical Engineers could never design an integrated circuit without the combination of Ohm’s Law and Kirchhoff’s Voltage and/or Current Laws from Physics II. Kirchhoff’s Current Law states that the algebraic sum of currents in a network of conductors meeting at a point is zero. This is the principle of Conservation of Electric Charge. Kirchhoff’s Voltage Law states that the algebraic sum of voltages in a closed loop is zero. This is the principle of Conservation of Energy. 

Mechanical Engineering is perhaps the widest branch of Engineering and contains endless principles from Physics I. Designing an Internal Combustion Engine wouldn’t be possible without the Laws of Thermodynamics and the Ideal Gas Law. Improving the efficiency of the engine couldn’t be done without the model of the Carnot Cycle.

Designing a submarine wouldn’t be possible without Archimedes’ Principle. This principle states that any object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object. In other words, the Buoyancy exerted on the submarine = the displacement of the water. And once again, Newton’s Laws of Motion come in to play. When it comes to the Design of a Mechanical System or Machine Component, the Second Law is used to analyze dynamic loading. The list goes on.

We can see that the most basic equations of Physics are responsible for some of the most incredible achievements in Engineering. From this perspective, we could say that Engineering is a branch of Physics or, furthermore, an application of Physics, because Engineering wouldn’t exist without Physics.