Dealing with Smoosh Poosh and Friction on Inclines

As a reminder, we have dealt with forces on inclines previously, during the BFPM model.  That's where you're starting from in the first problem on this worksheet, the object is moving down the incline at a constant speed.  There were some common issues that I noticed on many of the boards, and I attempt to address them in this short video clip.

So try to address these concerns for the forces you've diagrammed on your whiteboard.  Once your FAD is a right triangle, and you're following our guidelines for direction of smoosh poosh and direction of friction, compare whiteboards for part 1 as a class.  Do not erase your board when moving on to part 2.  In part 2 the only thing that changes is that the amount of friction decreases.  In other words, there's no longer enough friction to make a balanced FAD, and you'll now have an FU filling in the rest of that gap.  That'll affect the motion of the object, so I guess I wasn't truthful in saying that only one thing changes, several things will change.  Use your diagrams and graphs to figure out what they are.  Good Luck!