130 likes | 295 Views
March 29 th 2011. Vectors Review. A vector quantity is a quantity that is described by both magnitude and direction . A scalar quantity is a quantity that is described by its magnitude . Can you think of examples of each?. Vectors vs. Scalars.
E N D
March 29th 2011 Vectors Review
A vector quantity is a quantity that is described by both magnitude and direction. A scalar quantity is a quantity that is described by its magnitude. Can you think of examples of each? Vectors vs. Scalars
Three key requirements when using a vector diagram. a scale is clearly listed a vector arrow (with arrowhead) is drawn in a specified direction. The vector arrow has a head and a tail. the magnitude and direction of the vector is clearly labelled. In this case, the diagram shows the magnitude is 20 m and the direction is (30 degrees West of North or N30W). Drawing vectors to scale
Draw the following vectors to scale: • 80 N of force, N25E • 150 m/s, S35W • 1.5 N of force, E45N • 0.25 m/s, W60S Try a few.
When adding vectors we must use the head-to-tail-method using a scaled diagram. The vector that connects from the tail of the initial vector to the head of the last vector is the resultant vector. Choose a scale and indicate it on a sheet of paper. The best choice of scale is one that will result in a diagram that is as large as possible. Pick a starting location and draw the first vector to scale in the indicated direction. Starting from where the head of the first vector ends, draw the second vector to scale in the indicated direction. Label the magnitude and direction of this vector on the diagram. Addition of Vectors.
Draw the resultant from the tail of the first vector to the head of the last vector. Label this vector as Resultant or simply R. Using a ruler, measure the length of the resultant and determine its magnitude by converting to real units using the scale. Ex1. V1 = 15 N of force, N ;V2 = 25 N of force, E. Draw to scale and determine the resultant vector. Addition of Vectors Cont
By use of Pythagorean Theory, the resultant vector can be determined by using SOH CAH TOA Alternate approach to Ex 1.
Draw and add the following vectors to determine the resultant. 20 m, 45 deg. + 25 m, 300 deg. + 15 m, 210 deg. 15 m, 210 deg. + 25 m, 300 deg. + 20 m, 45 deg. Practice using Head to Tail method.
Pg.93 # 8, 9 Pg. 94 # 10, 11 Homework: