Midterm 2 F09
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DYNAMICS OF MECHANISMS MECH-314 MIDTERM EXAM 2 Thursday, November 12, 2009, 10:05 – 11:25 PLEASE READ THE FOLLOWING INSTRUCTIONS CAREFULLY: - STUDENTS ARE ONLY ALLOWED A ONE-PAGE (8.5” X 11”) CRIB-SHEET, WITH WRITING ON BOTH SIDES. - PLEASE ANSWER ALL QUESTIONS. - QUESTIONS MUST BE ANSWERED DIRECTLY ON THE EXAM PAPER, IN THE SPACE PROVIDED BELOW OR BESIDE THE QUESTIONS. Student Name: Student Number: Page 1 of 4
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Dynamics of Mechanisms
Transcript of Midterm 2 F09
DYNAMICS OF MECHANISMSMECH-314
MIDTERM EXAM 2
Thursday, November 12, 2009, 10:05 – 11:25
PLEASE READ THE FOLLOWING INSTRUCTIONS CAREFULLY:
- STUDENTS ARE ONLY ALLOWED A ONE-PAGE (8.5” X 11”) CRIB-SHEET, WITH WRITING ON BOTH SIDES.
- PLEASE ANSWER ALL QUESTIONS.
- QUESTIONS MUST BE ANSWERED DIRECTLY ON THE EXAM PAPER, IN THE SPACE PROVIDED BELOW OR BESIDE THE QUESTIONS.
Student Name:
Student Number:
Page 1 of 4
Problem 1: [25 + 25] For the mechanism shown below in the scaled position diagram: RBA = 8.34 cm, RCA
=9.48 cm, RCD = 16.53 cm, and RBC = 2.36 cm. The angular velocity of link 2 is rad/s cw, and the velocity of point D5 is VD5 = 30 î cm/s.
(a) Determine the magnitude and direction of the angular velocity of link 4 assuming general contact between links 2 and 3 (we do not assume rolling). Give the detailed set of velocity difference and/or apparent velocity equations that are necessary for the solution. Employ point OV and scale 1cm = 10 cm/s.
(b) Using the graphical representation developed for point (a), determine the magnitude and direction of the angular velocity of link 3 for the case when rolling contact is assumed between links 2 and 3. Give the detailed set of velocity difference and/or apparent velocity equations that are necessary for the solution.
OV
Page 2 of 4
Problem 3: [30 + 20] The scaled position diagram of a mechanism is shown in the figure: REA = 6 cm, RBA = 3 cm, RBE = 4.4 cm, RCB = 3.5 cm, RDC = 3.2 cm. The angular velocity of link 2 is given as
rad/s ccw (constant). Based on this, the following can be determined:
rad/s cw, rad/s ccw, and cm/s pointing in the direction of the vector from point E to C. Perform the complete acceleration analysis of the mechanism using graphical representation of the vector equations. Give the sets of acceleration difference and/or apparent acceleration equations necessary for this analysis. Employ origin OA, and scale 1 cm = 15 cm/s2. Based on this graphical representation (acceleration polygon),
(a) determine the magnitude and direction of the acceleration of point C5 (b) determine the magnitude and direction of the angular acceleration of link 5.
OA
Page 3 of 4
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