Sample Test 1 |
Quiz 1 - Chapter 4, 1 |
CH 4 : Multiple Choice Questions-1, 2, 15 |
exercises/problems -1, 2, 3, 5; If Ch. 4 problems seems difficult, skip to the Ch. 1 exercises/problems below then return to finish these later. |
CH 1: exercises/problems-34, 37, 38 (see exercise #4, Ch 4) for comparison and practice), 42, 44, 48, 50 |
DISCUSSIONS |
CH. 4
Multiple Choice Questions 1, 2, 15 each deal with Newton's first Law, which says if the net force is ZERO, the object undergoes uniform motion or remains at rest. |
exercises problems. |
1. F_{x} = 10*cos45 and F_{y} = - 10*sin 45 assuming the positive y directions is UP. |
2. Let the 270 N-force be along the positive x axis, and the 300 N-force be 60 degrees above the positive x axis. The components of the resultant are R_{x} = 300*cos 60 + 270 and R_{y} = 300*sin60 + 0 = 300*sin 60. Find the magnitude and angle using class notes. |
3. F_{x} = F*cos50 and F_{y} = F*sin 50 assuming the positive y directions is UP. |
4. The net force is vertically up with magnitude 5 = 2*T*sin 52.5. Solve for T = magnitude of tension force. |
5. F_{x} = 985*cos 31- 788*cos58 -
411*cos53 and F_{y} = 985*sin 31 + 788*sin58 - 411*sin53 Find the magnitude and angle using class notes. |
CH. 1 |
34. (a) quadrant 1 (b) quadrant 3 (c) quadrant 2 (d) quadrant 4 |
37. (a) The resultant is in the first
quadrant. (b) the difference is in the third quadrant. Use tail to tail method (c) the resultant is in the opposite direction as the vector in part (a). (d) the difference is in the opposite direction as the vector in part (b). Use tail to tail method. |
38. See hint to #4, Ch. 4. Same problem, different numbers. |
42. F_{x} = 20*cos37 and F_{y} = 20*sin 37 |
44. Starting with vector-A and going counter-clockwise:
Here are the x components: 12 cos 53, - 6cos60, 15cos40 . And here are the y components 12sin 53, -6sin 60, -15sin 40. |
48. Resolve the components as we did in problem 44. Add up the x-components to get R_{x}. Add up the y components to get R_{y}. Use the Pythagorean Theorem to get the magnitude. See class notes for the quadrant and angle. |
50. There are three vectors we want to add: The first vector has zero x-component, the second vector has zero y component, and the third vector has components given by F_{x} = 3.1*cos45 and F_{y} = 3.1*sin 45 (in the first quadrant.) See guidelines in #48. |
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