12-10-08

Today when I walked into Physics, I looked at the Daily Agenda for the class. Mr. Manning had written: 1. Graded Daily Question 2. Review Distance, Displacement, and Vectors 3. Vector Subtraction.

The Graded Daily Question was: A motorboat is travelling at 35 m/s in the 40 degrees direction. the boat enters a current moving at 15 m/s in the 270 degree direction, which provides it with an additional velocity. What is the boat's resultant velocity? First you must create a scale and come up with the new scaled measurements. Draw the 35 m/s vector in the 40 degree direction, then draw the 15 m/s vector in the 270 degree direction. Then you must find the missing vector (the resultant) and connect it from the beginning to the end. The final answer should be around 27.8 m/s at 15.6 degrees.

Next up on the agenda was reviewing the worksheet we completed in class yesterday called Vectors, Distance, and Displacement (pg. 17). This worksheet involved working vector addition. It as also based on our knowledge of distance, displacement, vectors, and resultants. While discussing this, Mr. Manning reminded us and reinforced that a larger picture drawn provides better ending results.

The last part of today's class was learning about subtracting vectors. We received the notes page for this lesson (pg. 18) when we walked into class. Subtracting vectors is the same as adding vectors, except when you have 2 vectors (A and B), to subtract A-B, you use A +(-B). B-A will provide a vector with the same magnitude but opposite direction. Another method for this is called the Tail-to-Tail Method, which Mr. Manning said most students prefer. Using the same vectors A and B, place them ail to tail. The magnitude of the difference is just the vector drawn from head to head. For the direction, the head of he difference vector points toward the term you say first in the subtraction. That is, for A-B, the arrowhead points to vector A; for B-A, the arrowhead points to vector B.

Problem #1a on worksheet 18