FIRST Lets get the HW ready AND lab notebooks. Agree/Disagree and sign with what you agree/disagree with

HOMEWORK FROM LAST TIME What do I need to go over with you before you potentially turn this in?

LETS GET STARTED LETS PICK THEM NAMES! HW TURN IN! LETS PICK THEM COLORS! LETS PICK UP THE IDEAS TO APPLY IN CLASS!

SCHEDULE FOR THE QUARTER TUES/WED: Confirming knowledge, pulleys THURS/FRI: X and Y with pulleys, ramps MON/TUES: ½ Ramps and pulleys together. ½ Review of quarter WED/THURS: 1/3 new physics, 2/3 End of Quarter examination

CLASS NOTEBOOKS OUT 7 MINUTES FOR THIS

BUT NOW! To get us started… You will try the front page (2 questions together, 1 below it) alone with your notebook. Explain Time: 6 minutes. Now compare with your partners and come to a consensus. Time: 4 minutes.

Time to hit…it is all about the Y velocity, distance and acceleration! Do they all have the same starting Y velocity? YES! Do they all have the same Y acceleration? NO! B has less b/c there is another force against motion.

Do they all have the same starting velocity? NO! C has an initial velocity! So A and B will hit with the same overall velocity (Remember about angles from same point) C will hit with more since started faster.

SUMMARY The ramp’s normal force made the object take more time to hit since it worked against the weight. That caused the acceleration to be less than gravity (Actually g*Sin θ) But the ramp will mean it will still hit with the same velocity at the bottom, because it will have less Y velocity but will have an X velocity to compensate.

I LOVE THIS QUESTION (because…) All that matters is the time in air. Which direction controls time in air? Y! So which shot has less Y velocity? The one to B, because it did not go as high.

N OW LETS DRAW FBD’ S FOR EACH OF THE SITUATIONS ON THE LAST ONE. R EAD 1 ST 1) Elevator moving up at a constant velocity 2) Elevator moving down at a constant velocity 3) Elevator moving up, speeding up 4) Elevator moving up, slowing down 5) Elevator moving down, speeding up 6) Elevator moving down, slowing down

SCENARIOMORE/LESS/EQUALIN WORDS WHYSOLVING FOR THE FORCE 1) Elevator moving up at a constant velocity 2) Elevator moving down at a constant velocity 3) Elevator moving up, speeding up 4) Elevator moving up, slowing down 5) Elevator moving down, speeding up 6) Elevator moving down, slowing down

N OW F OR N EW A PPLICATIONS TENSION is the force of a rope in contact with an object. In Newtons. KEY IDEA: One rope only has one tension. For our purposes: Two things connected by a rope has the same tension on each (N3L)

Lets do pulleys. Grab two masses. Hook one to one end, hold the string with your hand. The fixed pulley (pulley can’t move) allows you to pull in a different direction than the motion of the object. A movable pulley means you can lift with less force than the weight!

Put equal masses on each side. Now draw a FBD for each mass under your general picture..

Put unequal masses on each side. Now draw a FBD for each mass under your general picture. Remember to figure out which way the imbalance is!.

As one side gets more and more massive, what will happen to the acceleration? Is there a limit to the value? MY THINKING: “The weights oppose each other. As one gets heavier, its like the other weight is not really there. So its going be like its not opposed. Which would be free fall.

YOU FIGURE OUT: SCENARIO Take two larger masses and hang them on each end. We know that there is friction on the pulley. Figure out how you can determine how much friction there is on the pulley by using a tiny mass with the larger masses. This is a KEY TEST that you know what is going on.