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Elizabeth Young 1-12-09 Pd. 3 Today was a very laid back day in physics. GOOD NEWS THOUGH!!!!! T-SHIRTS ARE FINALLY HERE!!! If you haven’t already, pick yours up from Mr. Manning. They look awesome. __Today’s Objectives:__ Mr. Manning did check homework today. He checked problem pg. 16 #3. We then went over the answers and we were reminded to pay attention the direction of the vectors. If a vector is pointing left, then it has a negative velocity. I you forget this negative velocity, your answer will be wrong, SO BE CAREFUL! Then we did the daily question. It is as follows:
 * Pass out T-shirts
 * HW
 * HW Check
 * DQ
 * Practice page
 * 1) Using the graph below, find the impulse given by a bullet.
 * 2) If the mass of the bullet is .05 kg, what is the change in velocity of the bullet?



__Answers__ Area of Trapezoid=1/2(b1+b2)h A=1/2(.17+.07)(-100,000) A=-12,000 Ns Area of Triangle=(1/2)bh A=(1/2)(.07)(-200,000) A=-7000 Ns Total Area= Impulse= -12,000-7,000= -19,000 Ns

Impulse= Change in Momentum Impulse=m(change in v) -19000=.05(change in v)  Change in v= -380,000 m/s

After going over the daily question, Mr. Manning asked us to do pg. 17 from the packet he gave us last Friday. We worked out the problems with groups and then went over it as a class at the end of the period. The important equation to know to complete this worksheet is: (m1x v1)before+(m2x v2)before= (m1x v1)after+ (m2x v2)after Also remember that momentum MUST be the same before and after each problem

So that was physics today! Remember that the reading guide is due Wednesday, and remember to study for the test that is also on Wednesday.