Question

Choose the Correct answers: 1. What are the polar coordinates of the vector 3i-2j? (a) (3.6; 33.7) (b) (3.6; 146.3*) (c) (3.6;-33.7") (d) (4.2; 33.7) (e) (4.2;-33.7) 2. If vector A-)=3.21+4Sf and vector B->=5.71-19" , where i^ and j'are the units vectors along the x and the y directions respectively. If C-〉-3A->-28→, calculate the angle vector C-> makes with respect to the +x axes. (a) -840 (b) -96 (c) 849 (d) 969 (e) -6

Answer 1

A^vector = 3i^^- 2j^^W Vertical-bar A^vector Vertical-bar = squareroot 3^2 + 2^2 = squareroot 13 = 3.6 tan theta = -2/3 theta = -33.7 degree So as 3.6: -33.7 degree A^vector = 3.2i^^+ 4.5j^^, B^vector = 5.7i^^- 1.9j^^c^vector = 3A^vector - 2B^vector = > c^vector = [9.6 i^^+ 13.5 j^^] - [11.4 i^^p - 3.8 j^^] c^vector = -1.8i^^+ 17.3j^^tan alpha = 17.3/1.8 = > alpha = 84.05 degree therefore theta = 95.9 degree or 96 degree