# Physics 8-26-11 Velocity Problems 2

PHYSICS – Velocity problems from Thursday – you’re doing a great job on these! Let me know how the take home lab is going for you. I think it will be a good break from your typical type of homework!

Good luck on those five problems. Try not to look at your notes, but if you do, work it again without your notes! And make sure to do more than just show the math – be sure that I can also follow your logic in the formulas. Ditto with units, etc. Don’t give up on the tortoise and the hare. A couple of hints: remember the distance the tortoise travels is the same as the distance the hare travels plus the extra 20 cm he was ahead. Also, the time the hare raced is equal to the time of the tortoise minus those two minutes he rested. Now go have fun! ðŸ™‚

# Chemistry 8-26-11 SI Derived Units

CHEMISTRY – So you thought Goodman Road was getting crowded! How’s this for a “high density” city? Here’s the lecture from Friday on derived SI units. Great job on the density problems today! Remember, in chemistry we use math as a tool, therefore we might work problems a little differently in chemistry than you do in your math class. I think you’ve done a lot of this already, but make sure you understand the conceptual side of density as well!

When working these problems, don’t forget to follow the problem solving steps we discussed today. Analyze – write down what you’re given and what you’re looking for, plan – write a formula where you isolate the unknown on one side by itself, compute – plug in your data, numbers and units. Then cancel the units, and if they cancel correctly, go on to the calculator. Be sure and give your answer what the correct units. And finally, evaluate – does your answer make sense, have you used the correct units, do you have the correct sig figs? Wait – scratch that last thing, we’ll do sig figs in a couple of days. You’ll just have to wait! ðŸ™‚