# PHYSICS 11-10-17 Forces with Pulleys and Friction

PHYSICS: Here’s a different take on forces – an application of horizontal forces, vertical forces, friction, all at once! Wow! Great job on solving the problem – can you now go see if you can solve it by yourself?

Thanks, Matthew, for the visual of almost weightlessness! ðŸ™‚

# Physics 10-31-11 Friction on Inclines

PHYSICS: Who knew snow skiing could be so complicated! Well friction problems on an incline anyway. Here’s the lecture/problem review from Monday on friction problems on an incline. Remember, drawing the diagram is super, super important. Label all the forces, and apply the concepts you know about net forces and resultant forces. And practice!!

flickr photo by t i g

# Physics 10-28-11 Friction & Normal Force (& Zorba!)

PHYSICS: So why don’t things that are moving just keep moving? Here’s the intro lecture on friction. Remember a few key things. Net forces produce acceleration. You can find Ff a couple of different ways – it’ll be part of a net force equation and can be found from the coefficient of friction equation. If and ONLY if your object is moving at a constant velocity, Ff will equal Fa. Fn is only sometimes equal to Fw. If your object is pulled at any angle (or pushed), Fn will be a part of Fnet in the vertical direction. Is that enough for now? Have a great weekend!!

BTW – Did you figure out Zorba? The solution is at the beginning of this vodcast.

flickr photo by kbaird