Physics Sensei questions & answers
I Got the Homework Right After Several Tries. Am I Ready for the Exam?
The homework took a while. Some problems needed three or four tries, but eventually every answer turned green. Full marks. So you should be ready for the exam, right?
Maybe. It depends on what happened between those tries.
If you got the homework right after several tries, the number of tries matters less than one question: did you find your mistake, or did you change things until the answer worked?
What’s really going on
Online homework tells you right away if your answer is wrong. That feedback is useful, but it can also do your thinking for you.
There are two very different ways to use another try. You can find the mistake: reread, spot the missing force, fix the sign, and understand why. Or you can guess: flip a sign, try a different formula, change cos to sin, until the system says yes.
Both end with a green check. Only the first one prepares you for an exam, where there’s one try and no green check to tell you when to stop.
Why guessing makes it worse
Guessing works surprisingly often on homework, because there are only a few things to change. Each lucky guess feels like getting it right.
But the exam has no feedback. The habit of trying things until something works has nothing to work with.
Why it’s hard to change
When you’re tired and the homework is due at midnight, guessing is faster than finding the mistake. And the grade is the same either way.
That’s why you need a check that doesn’t care about the grade.
The fix: the cold redo
Find out whether you’re ready by redoing the hard problems later, with no feedback and one try.
Try this before your next exam: the cold redo
- As you do homework, mark every problem that took more than one try.
- Next to each one, write which kind of try it was: “found the mistake” or “guessed.”
- Two days later, redo every marked problem on paper. One try, no notes, no system to check you.
- Ask: What are they asking? What do I know? What’s the big idea? Check your answer only at the end.
- Right on the cold redo? You’re ready on that topic. Wrong? That’s what to study before the exam.
What changes
The cold redo takes an hour or two before each exam. It replaces a lot of anxious guessing about whether you’re ready.
And over time, you’ll guess less on the homework itself, because you’ll know the cold redo is coming.
A green check after five tries isn’t the same as being ready. A cold redo tells you the truth.
Practice problems built for this
On Physics Sensei, every problem asks you to try it first, and the feedback names your exact slip instead of just saying “wrong.” That makes it easy to find the mistake instead of guessing. Every problem is solved step by step, and then you get one more like it, with new numbers: a cold redo, built in.
Your next step: mark every multi-try problem on your next homework, then do the cold redo two days later. Use Physics Sensei to practice the ones you miss.
More questions about studying and grades? See them all here.
Raul, Physics Sensei
