Study Guide

# Physics Basics - Common Mistakes

## Common Mistakes

Ever noticed that telling people we’re studying physics produces a look, a mixture of admiration and pity, from those people? We have too.

What’s up with the look? Well, physics has a bit of a reputation. Not for smoking behind the bike-shed or going to raucous parties, though. Physics has a reputation for being, how can we put this... really freakin’ hard. It can be, sometimes, but it doesn’t have to be that hard.

A big part of the problem is that students fall into the same traps year after year. So let’s take a look at some of the most common mistakes of physics students everywhere and how we can avoid making them.

Problem Solving

Physics is all about problem solving. If we can’t solve problems, we can’t do physics. So having a step-by-step approach to solving any problem on our back pockets will be handy. Here are the steps we prefer:

1. Get the lowdown of the problem and really understand it
2. Doodle a diagram
3. Write down any given numbers—they are usually very handy. (Example: “final velocity, vf = 32 m/s”)
4. Search the text for context that represents hidden numbers. (Example: If the object “started at rest” or was “dropped” then its initial velocity is zero.)
5. Strategize and select the appropriate equations from our utility belt.
6. Solve equations and show our work in full.
7. Check our work.

Include Units

Somewhere on Earth, a physics student loses a point for failing to include units every 4 seconds. Units are vital pieces of information. It’s the difference between sixty meters and sixty purple elephants. If we make the physics teacher guess, they’ll choose elephants every time, so we better give them a hand.

Units are also a great tool for checking equations. If we want to double check that we rearranged an equation correctly, we can check that the units on each side of the equation. If the units match, we’re good.

Human Error

When doing experiments, error (otherwise known as uncertainty) always exists. Any measurement we take has uncertainty, and human reaction times (like pressing a stopwatch) also play into this. But “human error” is not the same as experimental error. If we make an actual mistake during an experiment, it’s time to start over. Experimental error is unavoidable; human error is a failing grade waiting to happen.