test19 - COE 2001 —— Test 1 — Summer 2007 Name.527...

Info icon This preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: COE 2001 —— Test 1 — Summer 2007 Name: (.527 PLEASE NOTE: 1. If axes are specified for a given problem, you are to use them. Do not change them in any way or you get a 0 (zero) to that question. Show all work. If you make an assumption, state it clearly. Provide units with your answers, and box them. Use the back of the equation sheet as scrap paper if needed. The “lb” unit means “lb—force” in this test, NOT “lb-mass” (i.e. do NOT multiply by gravity to get a force!). Define clearly any new variable you introduce in a problem based on the givens. For the second problem, you are to use vectors to solve it, i.e. write forces and moment arms as vectors and calculate moments using cross products. Failure to comply will result in a 0 to the question even it you arrive at the ri ht answer in some di erent manner. P399953!" Pb. I (50 pts) — Out in your backyard, there’s a big tree with a branch loaded as follows (see figure (a) below): your cat, which weighs 10 lbs, is eyeing a 2 lbs bird resting on a small offshoot branch. Your little sister, who weighs 60 lbs, is sitting on the swing and calling for you to come give her a push. Your dad is trying to get the cat down and is pulling on a rope tied around the branch to do so, at an angle of 45° from the horizontal, with a force of 50 lbs. At the root of the branch (where it attaches to the main body of the tree, ie point A), you are to assume that the tree exerts on the branch a vertical force Ay of 100 lbs, a horizontal force Ax of 40 lbs, and a clockwise moment MA of 2,000 lb.in. The main branch (ie the horizontal part only, without the offshoot), its dimensions, and the forces and moments that are applied to it due to your cat, the bird, your sister and your dad, can be modeled as drawn in figure (b). (This drawing is the FBD of the branch) Based on this drawing, please answer the following questions: 1." Calculate the total force (ie sum of the forces) applied to the branch, both in the x and the y direction. 2. Calculate the total moment (ie sum of the moments) applied to the branch at point A (ie at its root). Is it a positive or negative moment? 3. For the branch to be in equilibrium, the sum of the forces and the sum of the moments applied to it must both be equal to 0 (zero). Is the branch in equilibrium? Why or why not? y rm“ -—-——9 X chr, lull/LL Pb 11(50 pts) — A humpback whale lost in the San Francisco inland waterways is being dragged back out to the Pacific Ocean by two helicopters, each attached to the whale by a cable, as shown below. The orientation of cable 1 is given by 2 points, A and B, with the following coordinates: A(1,1,1) and B(4,3,5) in the given coordinate system. Its tension T1 has magnitude 10 N. Cable 2 is similarly oriented along points C(2, -O.5, 1) and D(5, —2, 4) and its tension magnitude T2 is 15 N. Both forces are oriented as depicted in the figures below. The center of gravity G of the whale is the origin of the coordinate system, ie G has coordinates (0,0,0). Express the force T1 as a vector, ie calculate its components in the given coordinate system. Express the force T2 as a vector, ie calculate its components in the given coordinate system. Calculate the moment due to T1 at G, as a vector with its components expressed in the given coordinate system. Calculate the moment due to T2 at G, as a vector with its components expressed in the given coordinate system. 9.99.59!" ...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern