Practice Test 4 Sections 6.6, 6.7, 9.1, 9.2, and 9.3 Sketch the vector as a position vector and find its magnitude. 1) v = -2i + 5j 12) v = 7, θ = 225° Solve the problem. 13) The magnitude and direction of two forces acting on an object are 35 pounds, N45°E, and 55 pounds, S30°E, respectively. Find the magnitude, to the nearest hundredth of a pound, and the direction angle, to the nearest tenth of a degree, of the resultant force. y 6 4 2 -6 -4 -2 2 4 6 x -2 14) Two forces, F1 and F2 , of magnitude 60 and 70 -4 pounds, respectively, act on an object. The direction of F1 is N40°E and the direction of F2 is N40°W. Find the magnitude and the direction angle of the resultant force. Express the direction angle to the nearest tenth of a degree. -6 Let v be the vector from initial point P1 to terminal point P2 . Write v in terms of i and j. Use the given vectors to find the specified scalar. 15) u = 11i + 4j and v = -6i - 5j; Find u · v. 2) P1 = (6, 4); P2 = (-5, -4) 3) P1 = (2, 3); P2 = (-6, 3) 16) v = 6i + 2j; Find v · v. Find the specified vector or scalar. 4) u = -7i - 3j, v = -5i + 7j; Find u + v. A) -13i + 4j B) -2i - 13j C) 2i + 4j D) -12i + 4j 17) u = -6i + 10j, v = -7i - 6j; Find (-5u) · v. 18) u = 6i + 10j, v = -2i - 8j, w = -4i - 2j; Find u · (v + w). 5) u = -9i - 2j, v = 5i + 7j; Find u - v. Find the angle between the given vectors. Round to the nearest tenth of a degree. 19) u = -3i + 6j, v = 5i + 2j 6) v = 8i + 2j; Find 3v. 7) u = -7i + 1j and v = 8i + 1j; Find u + v . 20) u = 3j, v = 8i + 2j Find the unit vector that has the same direction as the vector v. 8) v = 5i + 12j Use the dot product to determine whether the vectors are parallel, orthogonal, or neither. 21) v = 3i + 2j, w = 3i - 2j 9) v = -9j 22) v = 3i - j, w = 6i - 2j Write the vector v in terms of i and j whose magnitude v and direction angle θ are given. 10) v = 8, θ = 30° 23) v = 4i + 3j, w = 3i - 4j 24) v = 3i, w = -2i 11) v = 12, θ = 180° 1 Solve the problem. 25) A person is pulling a freight cart with a force of 59 pounds. How much work is done in moving the cart 80 feet if the cart's handle makes an angle of 30° with the ground? Solve the problem. 31) The arch beneath a bridge is semi-elliptical, a one-way roadway passes under the arch. The width of the roadway is 38 feet and the height of the arch over the center of the roadway is 11 feet. Two trucks plan to use this road. They are both 8 feet wide. Truck 1 has an overall height of 10 feet and Truck 2 has an overall height of 11 feet. Draw a rough sketch of the situation and determine which of the trucks can pass under the bridge. Graph the ellipse and locate the foci. x2 y2 26) + =1 25 49 y 10 Find the vertices and locate the foci for the hyperbola whose equation is given. 32) 49x2 - 16y2 = 784 5 -10 -5 5 10 x Match the equation to the graph. y2 x2 33) =1 9 16 -5 -10 A) 6 y 5 Graph the ellipse. 4 27) 16(x - 2)2 + 9(y - 1)2 = 144 3 y 2 10 1 5 -6 -5 -4 -3 -2 -1 -1 1 2 3 4 5 6x 1 2 3 4 5 6x -2 -3 -10 -5 5 10 -4 x -5 -6 -5 B) -10 6 y 5 4 Find the standard form of the equation of the ellipse satisfying the given conditions. 28) Major axis horizontal with length 12; length of minor axis = 6; center (0, 0) 3 2 1 -6 -5 -4 -3 -2 -1 -1 -2 29) Foci: (0, -2), (0, 2); y-intercepts: -3 and 3 -3 -4 -5 Convert the equation to the standard form for an ellipse by completing the square on x and y. 30) 4x2 + 16y2 + 8x - 64y + 4 = 0 -6 2 Convert the equation to the standard form for a hyperbola by completing the square on x and y. 37) y2 - 16x2 - 2y - 32x - 31 = 0 C) 6 y 5 4 3 Find the location of the center, vertices, and foci for the hyperbola described by the equation. (x + 2)2 (y + 4)2 38) =1 64 100 2 1 -6 -5 -4 -3 -2 -1 -1 1 2 3 4 5 6x -2 -3 Find the standard form of the equation of the hyperbola. 39) -4 -5 6 -6 y 5 D) 6 4 y 3 5 2 4 1 3 2 -6 -5 -4 -3 -2 -1 -1 1 -6 -5 -4 -3 -2 -1 -1 1 2 3 4 5 6x -2 1 2 3 4 5 -3 6x -4 -2 -5 -3 -6 -4 -5 A) x2 y2 =1 9 25 B) y2 x2 =1 25 9 C) x2 y2 =1 25 9 D) y2 x2 =1 9 25 -6 Find the standard form of the equation of the hyperbola satisfying the given conditions. 34) Foci: (0, -10), (0, 10); vertices: (0, -6), (0, 6) Use the center, vertices, and asymptotes to graph the hyperbola. (y - 2)2 (x + 1)2 40) =1 4 16 35) Center: (6, 5); Focus: (3, 5); Vertex: (5, 5) Use vertices and asymptotes to graph the hyperbola. Find the equations of the asymptotes. 36) 9x2 - 4y2 = 36 y 10 y 5 10 -10 5 -5 5 10 x -5 -10 -5 5 10 x -10 -5 Find the focus and directrix of the parabola with the given equation. 41) y2 = 28x -10 3 Match the equation to the graph. 42) (x + 2)2 = 8(y + 2) Find the standard form of the equation of the parabola using the information given. 43) Focus: (0, 21); Directrix: y = -21 A) 10 y Convert the equation to the standard form for a parabola by completing the square on x or y as appropriate. 44) y2 - 4y - 2x - 2 = 0 5 -10 -5 5 10 x Find the vertex, focus, and directrix of the parabola with the given equation. 45) (x + 4)2 = 20(y + 2) -5 -10 Graph the parabola with the given equation. 46) (y - 1)2 = 5(x + 2) B) 10 y 10 y 5 5 -10 -5 5 10 x -10 -5 -5 5 -5 -10 C) -10 10 y 5 -10 -5 5 10 x 5 10 x -5 -10 D) 10 y 5 -10 -5 -5 -10 4 10 x Answer Key Testname: PRACTICE TEST 4 1) v = 29 26) foci at (0, 2 6) and (0, -2 6) y y 10 6 4 5 2 -10 -6 -4 -2 2 4 6 -5 5 10 x 5 10 x x -5 -2 -4 -10 -6 27) y v = -11i - 8j v = -8i D -14i - 9j 24i + 6j 5 5 12 8) u = i+ j 13 13 2) 3) 4) 5) 6) 7) 10 5 -10 -5 -5 9) u = -j 10) v = 4 3i + 4j 11) v = -12i 7 2 7 2 12) v = ij 2 2 -10 13) F = 57.04; θ = -23.6° 14) F = 99.37; θ = 93.7° 15) -86 16) 40 17) 90 18) -136 19) 94.8° 20) 76° 21) neither 22) parallel 23) orthogonal 24) parallel 25) 4087.6 ft-lb 28) x2 y2 + =1 36 9 29) x2 y2 + =1 5 9 30) (x + 1)2 (y - 2)2 + =1 16 4 31) Truck 1 can pass under the bridge, but Truck 2 cannot. 32) vertices: (-4, 0), (4, 0) foci: (- 65, 0), ( 65, 0) 33) D y2 x2 34) =1 36 64 (y - 5)2 35) (x - 6)2 =1 8 5 Answer Key Testname: PRACTICE TEST 4 36) Asymptotes: y = ± 3 x 2 46) 10 y y 10 5 5 -10 -10 -5 5 10 x -5 5 -5 -5 -10 -10 37) (y - 1)2 - (x + 1)2 = 1 16 38) Center: (-2, -4); Vertices: (-10, -4) and (6, -4); Foci: (-2 - 2 41, -4) and (-2 + 2 41, -4) 39) B 40) y 10 5 -10 -5 5 10 x -5 -10 41) focus: (7, 0) directrix: x = -7 42) D 43) x2 = 84y 44) (y - 2)2 = 2(x + 3) 45) vertex: (-4, -2) focus: (-4, 3) directrix: y = -7 6 10 x