Good Practice Guide for Answering Example problems
- Draw a diagram. Most of these questions need a bit of insight into what the problem looks like. From there, it's just "find the right equation and do some maths". Without the diagram, I don't know if you even understood what the question was asking you.
- Label a diagram. I found it useful to have different arrows to mean different things. Try to have a convention for when an arrow means Force or Velocity or Acceleration.
- Say what you're doing. For example : Conservation of Momentum, Newton's Second Law, and then underline it.
- Underline the answer. Underlining the answer makes it much easier to see at a glance if you're right or wrong.
- Remember the units. Otherwise the answer is meaningless.
- Use sensible units. Even if they're not SI. For example ionisation energies are much better in electron-volts than Joules.
- Leave it in algebra until the last line. Some things may cancel as you manipulate the algebra, don't put in the numbers until you have an equation of the form Answer = Algebraic expression
- Be tidy. Don't squash up equations all onto one line - leave lots of white-space on your page. Diagrams look nicer using a ruler.
- Staple your solutions together. There's less chance of me losing something. Or you forgetting it.
- Hand in on time. Otherwise you will fall behind. The course is quite fast-paced and we need time to do some revision too.
- Answer all the questions set.
- If there's something that's confusing you... either in lectures or on the problem sheet, you can mention it in pencil on your script, so I know what to prepare for the next tutorial.
- If you're unsure about a method... you can always put queries on your script in pencil.
Here's an example question and the example solution, that illustrates some of the above.
Question 1 A rollercoaster sets off from a height of 100M.
(A) How fast is it going when it reaches the ground (you may ignore friction.)
(B) It travels vertically along the ground before coming to rest. If the brake comes on with a force of 10N and if it had 30kJ of energy at the bottom of the slope: how long does it take to come to rest?
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