Dubai Year 11 Engineering Mathematics Revision Booklet (End of Term 1 Exam) 1 LC 2 Chapter 8.1 Geometric Vectors 1. Choose the correct answer (i) A quantity with only magnitude is called a _____. (a) Matrix (iii) Resultant (b) Vector (iv) Scalar (ii)The sum of two or more vectors is called _____. (c) The magnitude (iii) A scalar (d) The resultant (iv) The zero vector (iii)If both the initial and terminal points of a vector are at the origin, the vector is __________. (i)Positive (iii) The zero vector (ii)linearly independent (iv) Negative (iv)The magnitude of the zero vector is _____. (i) 0 (iii) – 0 (ii) 1 (iv) – 1 (v)A vector that has a magnitude of one is called a _____. (i) Scalar (iii) one vector (ii) unit vector (iv) vector 2 2. (i) Use a ruler and protractor to determine the magnitude (in centimeters) and the direction of n . Solution Sketch the vector in standard position and measure the magnitude and direction. The magnitude is 2 centimeters, and the direction is 20. (ii) Find the sum of v and w using: a. the parallelogram method. b. the triangle method. c. Compare the resultants found in both methods. Solution a. Copy v then copy w placing the initial points together. Form a parallelogram that has the two vectors as two of its sides. Draw dashed lines to represent the other two sides. The resultant is the vector from the vertex of v and w to the opposite vertex of the parallelogram. b. Copy v then copy w so that the initial point of w is on the terminal point of v . The resultant is the vector from the initial point of v to the terminal point of w . c. Use a ruler and protractor to measure the magnitude and direction of each resultant. The resultants of both methods have magnitudes of 2.6 centimeters and directions of 42. So, the resultants found in both methods are equal. 3 (iii) RECREATION A hang-glider traveled forward at 4 m/s and descended at 2 m/s. Determine the magnitude of the resultant velocity of the hang-glider. Solution Let 1 centimeter represent 2 m/s. Draw two vectors, f and d , to represent the forward velocity and the descending velocity of the hang-glider, respectively. Use the parallelogram method. Copy the forward velocity vector. Then copy the descending velocity vector placing the initial point at the initial point of the forward velocity vector. Draw dashed lines to represent the other two sides of the parallelogram. The resultant velocity of the hang-glider is the vector from the vertex of the two original vectors to the opposite vertex of the parallelogram. Measure the resultant, 2.3 centimeters. Multiply the resultant’s magnitude by 2 to determine the magnitude of the resultant velocity of the hang-glider. 2.3 cm 2 m/s = 4.6 m/s The hang-glider is moving at 4.6 m/s. (iv) Use the triangle method to find 2 v - 3 w . Solution Rewrite the expression as a sum. 2 v - 3 w = 2 v + (-3 w ) Draw a vector twice the magnitude of v to represent 2 v . Draw a vector with the opposite direction to w and three times its magnitude to represent 3 w . Place the initial point of the second vector on the terminal point of the first vector. (Tip-to-tail method) The resultant vector is the answer. 4 Chapter 8.2 Algebraic Vectors 3. (i) Write the ordered pair that represents the vector from X(-2, 4) to Y(4, -6). Then find the magnitude of XY . (ii) Let m = 2, -3, n = 1, 5, and p = -2, 4. Find each of the following. a. n +p Answer ………………………. c. 3 n b. m - p Answer………………………………. d. 2 m + 3 p Answer………………………………. Answer………………………………. (iii) Write AB as the sum of unit vectors for A(3, -2) and B(7, 4). Answer………………………………. Chapter 8.3 Vectors in Three-Dimensional Space 4. (i)Write the ordered triple that represents the vector from X(4, 2, -5) to Y(3, -4, 1). Answer………………………………. (ii) Suppose the flight of a baseball passed through points at (2, 6, 9) and (8, 4, 7), in which each unit represents a meter. What is the magnitude of the displacement the baseball experienced in traveling between these two points? Round to the nearest tenth. Answer………………………………. (iii) Find an ordered triple that represents 4 p - 3 q if p = 2, 5, 3 and q = (4, -2, 1). Answer………………………………. 5 (iv) Write AB as the sum of unit vectors for A(4, 2, 6) and B(-3, 8, -1). Answer………………………………. Chapter 8.4 Perpendicular Vectors (i) Find each inner product if p = (3, 7), q = (2, -3), and m = (9, 6). Are any pairs of vectors perpendicular? a. p q Answer…………………… b. p m c. q m Answer……………………… Answer……………… (ii) Find the inner product of a and b if a = -4, 2, 5 and b = 3, 6, 1. Are the two vectors perpendicular? Answer……………… ……………… (iii) Find the cross product of v and w if v = 5, 2, 3 and w = -2, 5, 0. Verify that the resulting vector is perpendicular to the two original vectors. Answer…………………………… Chapter 8. 6 Vectors and Parametric Equations 5. (i) Write a vector equation describing a line passing through P1(3, 2) and parallel to a = 4, -1. 6 Answer……………………………… (ii) Find the parametric equations for a line parallel to q = 4, -2 and passing through the point at (-1, -3). Answer……………………………… (iii) Write parametric equations of y = 3x – 5. Answer……………………………… (iv) Write an equation in slope-intercept form of the line whose parametric equations are x = 3 + 2t and y = -1 – 4t. Answer……………………………… Good Luck 7