Physics 218: Mechanics Instructor: Dr. Tatiana Erukhimova Lecture 8

Adding Vectors by Components 1.Draw a diagram 2.Choose x and y axes. Choose them in a way that make your work easier. (E.g. choose one axis along the direction of one of the vectors so that the vector will have only one component). 3.Resolve each vector in x and y components 4.Calculate each component using sine and cosine. Be careful with signs: any component that points along the negative x or y axis gets a negative sign. 5.Add the x components together to get the x component of the resultant. Similar for y: V x =V 1x +V 2x +… V y =V 1y +V 2y +…

6. If you want to know the magnitude and direction of the resultant vector,

Russian fable: Swan, Crawfish, and Pike Lake FcFc FpFp River FsFs Find F s and F c if F p, θ, and  are given Despite their huge effort the box does not move!

An airplane trip involves three legs, with two stopovers. The first leg is due east for 620 km; the second leg is southeast (45 0 ) for 440 km; and the third leg is at 53 0 south of west for 550 km. What is the plane’s total displacement?

Given two vectors, and a) Find the components of the vector b) Find the magnitude of and the tangent of the angle makes with the x axis. Quiz

Have a great day! Reading: Chapter 4 Hw: All Chapter 4 problems and exercises