# Physics 10-26-11 Newton’s 2nd & 3rd Laws

PHYSICS: So an object at rest can be at equilibrium, but what about an object that is moving? And how does equilibrium relate to Newton’s first law? Or Newton’s second law? And what if you don’t have balanced forces. Here’s the lecture from Wednesday on just that! Now remind me, net forces produce what?

# Physics 9-9-11 Free Fall Problems Review

PHYISCS – Here’s a question – how could this kid figure out how tall this cliff is? From Friday, here are a few free fall problems that we worked in class. Well, since you are doing such a GREAT job on labs, and since we ran out of time, I’ve posted a review that goes into a little more detail on #32, the “ball dropped from the top of a building and thrown up from the ground at the same time” problem and then a few from me that I thought would help as you work on the homework. DON’T WATCH THIS FIRST!! Try to work the homework problems by yourself first before you look in your notes or watch the vodcast!

Draw a picture, write down what you know and are looking for. What formula fits? On the problems with something going up and then dropping something else, like the pelican or the parachute, don’t forget that the item dropped has the velocity of the first thing. And to find how far apart they are, you usually have to figure in that the first thing was still moving when the second thing was dropped. Make sense? And be careful to keep positive and negative straight! Good luck – you’re doing a great job with these. I’m really proud of you!! Have a great weekend!

# Physics 9-7-11 Free Fall Acceleration

PHYSICS – So how do you like free fall? Here’s the lecture from Thursday on acceleration due to gravity. Hey, what’s your reaction time? Did you figure out why you can’t catch the dollar bill? Also, will this be number 3 or 4 in your lab book?. Put your data in a table and be sure and show all your calculations/work. (Don’t forget that all labs, these and the labs you’ve done that have reports on lab sheets are due on Monday.) Let’s play with the problems tomorrow and see if we can do something useful with free fall!

# Physics 9-1-11 Acceleration, Pt. 2

PHYSICS: Hey guys, here’s the last of the acceleration formulas. Good job with the derivations! You’re doing really well with them – stay with it! Carefully examine what you know with the formulas you have that might fit. And if they don’t, examine what you do know that could lead you to what you need to know. You know? π

Tonight’s problems might be a little challenging, but you can do it!! Do you need some extra practice rearranging the formulas, or just working the problems? Help session next Tuesday morning. Somebody better text me!

# Physics 8-31-11 Acceleration

PHYSICS: Great intro to acceleration! How do you feel about the formulas you helped me to derive? Go ahead and start the homework, and we’ll finish the last formula tomorrow – yes, there’s just one more. I think you’ll come to find these are a ton better than some of the velocity problems you did. List what you are given and what you’re looking for – don’t forget things like “starts from rest” and “came to a stop.” Then, just find the formula that contains the variables you are looking for. Easy peazy! Okay, maybe not that easy! π