You Can’t Push a Rope – Engineering at its Simplest

You can’t push a rope.
I had a professor who liked to say that engineering school could be summed up in two sentences:

1. f=ma
2. You can’t push a rope.

Although humorous, this does demonstrate an important problem solving skill that all engineers need to have.

Several times in engineering school, I would solve one of my homework problems, simply write the answer, and move on without taking a step back and asking myself, “Does this answer actually make sense?”.  🤔

To use my professor’s saying as an example, let’s say you’re using a pulley to lift a certain amount of weight off of the ground. The questions asks, “how many pounds of force is required to accelerate the weight off the ground?”

Many of us might get a negative answer, which could come as a result of making a small mathematical error. However, negative tension in a rope means that you have to push the rope in order to lift the weight.

Does this make sense?

Of course not! 🤦‍♂️

So many people just plug & play from the equation sheet and don’t step back to consider if their answer is reasonable. This problem can develop as early as grade school, where Tim & Kelly have 2.75 sons, or Jason works on the -0.5th floor of the building.

I think that my professor’s quote demonstrates two very important things that an engineer should walk out of school with:

1. The Book Smarts: which include math skills and a solid understanding of equations.

2. The Street Smarts: the critical thinking skills required to validate your designs based in reality.


Have you ever come up with any humorous solutions that made no sense? Share them in the comments!