Oh, and I forget to include the advice my husband (PhD in physics) gave my son (repeatedly) when he was taking AP Physics B a couple years ago. I’ve passed this advice on to a few people, and they said it was helpful.
The short form of the advice is, “Use lots of paper, and write clearly.”
The long form is, when you are doing a physics problem:
- The first thing to do is to write down all the things you know. Like: at t = 30, v = 60 km/h
- Next, draw a picture of what is happening and label the thing you want to figure out.
- Write down the relevant equations that you know.
- Solve the problem using the equations but without plugging in the actual numbers. Use the units to make sure that you are computing the right thing. For example, you know that velocity can be expressed as kilometers per hour, which is km / hour. So, the equation you use has to give the right units. That's a simple example, but the same thing applies something like Newtons (kg * m/s^2).
- Only plug the numbers from the problem in at the end.
- Make sure the answer makes sense.