Physics Sensei questions & answers
Why Can I Follow the Lecture but Can’t Solve Physics Problems on My Own?
In lecture, everything makes sense. Your professor works a problem on the board, and each step follows from the last. You could explain it to a friend.
Then you sit down with the homework. Same topic. You stare at the first problem, and nothing happens. You don’t even know how to start.
If you can follow the lecture but can’t solve problems on your own, you’re missing one specific thing. And once you see it, you can practice it.
What’s really going on
Every solution is full of decisions. Which object should I look at? Which direction is positive? Is this a forces problem or an energy problem? Which equation fits?
In lecture, your professor makes all of those decisions for you. You only have to check that each step makes sense, and it does. That’s following.
Solving means making the decisions yourself. It’s like riding in a car versus driving it. A passenger can follow every turn. Only the driver has to choose them.
Why rewatching makes it worse
When you get stuck, it’s natural to go back to the lecture or the worked example. It makes sense again, which feels good.
But you’re back in the passenger seat. You get better at following, and the decisions stay hidden. So the next time you sit down alone, you’re stuck in the same place.
Why it’s hard to change
The decisions are hard to see. In a worked example, they don’t look like decisions. They look like obvious steps, because someone already made them.
So you need a way to find them on purpose.
The fix: hunt for the decisions
Before you can make the decisions yourself, you need to see where they are. Then practice making them.
Try this with your next worked example: the decision hunt
- Take a worked example from class or the textbook. Cover everything but the problem.
- Before you uncover each step, ask: What decision comes next? Write your guess, like “pick the block as the object” or “use energy, because there’s a height.”
- Uncover the step. Did you make the same decision? If not, write down why the example chose what it did.
- Count the decisions in the example. Most have three to five.
- Now try a similar problem from scratch. At each decision, ask: What are they asking? What do I know? What’s the big idea?
Decisions you’ve practiced making stop being hidden. They start to feel like the obvious next step, the way they look when your professor does them.
What changes
At first, your guesses will often be wrong. That’s the point. Each wrong guess shows you a decision you didn’t know was there.
After a few examples, you’ll start to see the same decisions coming up again and again. That’s when homework problems stop feeling blank.
Following is riding along. Solving is driving. Practice the turns.
Practice problems built for this
On Physics Sensei, every problem is solved step by step with the same five questions: What are they asking? What do I know? What’s the big idea? Do the math. Does it make sense? Each step shows the decision being made, and each problem asks you to try it first. Then it gives you one more like it, with new numbers, so you can practice making the decisions yourself.
Your next step: try the decision hunt on one worked example from your last class. Then solve one problem on Physics Sensei from scratch.
More questions about studying and grades? See them all here.
Raul, Physics Sensei
