{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Exam_3_S11_Solution

# Exam_3_S11_Solution - Name ME 577 Exam 3 1 Suppose someone...

This preview shows pages 1–6. Sign up to view the full content.

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

View Full Document

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

View Full Document

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

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Name ME 577 - Exam 3 1. Suppose someone is in the weight room exercising. They’ve just finished the aerobic part of their workout and they have started strength training. Now assume that they are starting by doing some leg extensions. Effectively they are in a seated position, pushing up on a foam-covered bar while raising the legs. The knee joint is fixed and the bar always exerts a force normal to the lower leg. For this problem, assume that the tibia makes an angle of 45° with horizontal. (15 points]. First, draw a free body diagram of the lower leg (don't forget the coordinate system). W ' Wing? Describe any lengths or angles you need in variable form. ou hold your leg at 45°, rive an expression for the force developed in the muscles (you may assume smg e—fTe no moment model). You may treat the knee as a fixed point. Q ’ “1E2 Wkl’TUWW ‘ (wuw'c ) l’xr / x p \ ax WT and”; Ag 3“ AC4 .3 Y; 77 \ CV) Elm VT \ \ / M ~ / M9 XIX“; / £9 Z A; w J \. WK a \ Jr 3"“. fﬁ-Q wéﬂ v Mi? Slang 9 LVﬂ a) ~E5/ -— LSFM) r. O / M r (- L .3 L5 \\_ﬁ_~’/ Sly/6 W / LP? ‘3'”9597 r W ‘9 '«X’l ~ muLnl’J ‘WW’O Name Lastly, assume the lower leg is moving and write out the position, velocity, and acceleration of the center of mass of the lower leg in terms of its length and rotation angle. You may assume that the lower leg's mass center is exactly halfway between its ends. How does the muscle force change (anthhe same position of the leg) if the rotation angle is dG/dt = 1.5 rad/s and‘tbfe d29/dt2 = 4 rad/5A2. l :5: zLéér l - Y9; ,2 ca qé : —"£L\$9§r‘b Etsefa - T GD zM/L v "/LQ - i L (f / L 4: ': “ab S'ﬁDrrLP-rﬁvr 7 ‘vwsiv't‘ﬂ ' 9 w '75 i “Mi: +21, be Name 2. Consider a static analysis of an adult picking up a 30 lbs. child and holding the child at arm’s length (approximately 2.5 ft. from the shoulder). Assuming the shoulder lines up with the vertical axis of the spine, and the distance from the vertebral body to the erector spinae muscle is 2 inches behind the spine, calculate the conlpreﬂve and shear loads on the spine as well as the nge erector spinae muscle for static conditions. Assume that the head and torso weight 40 lbs. (2 inches in front of the spine) and the two arms weight 10 lbs. (10 points). 1 5Cyl” {Dina/3V4? \ / 3M] ‘ \ 1 WWW 4):? I am 5?me w . . \ SC -_ < aux EWch 5““ l k \ W053 ‘/ ') 6PM l . We u \ W \l \ ﬂitolﬂ’l i i l “ <1 i was} l SC \$5 F a // / l7? E9 A \/ A I N’%' Wcﬁ 1‘ ( E9 Lawm ‘1 ?,‘5 ~.(:. V/M/ Z soils .w y / f “‘3 “Ac W 4% g‘ 372%? 1: : O , W comma W». - . :\ v S§ a ‘ 3 O E ' "\$291. 49¢ —— (NHT-LW" \ wt )1 - ‘2 " - ' M 'v 0 i l / W66 1;, Q d F —— r) ommu‘rcl .— g/wavm We “W” ] EL) E8 I l W J- W 5 > claim {Mu—Ti + J’Mm D C) : {if /‘ €55 ; //—-w Name 3. How many cervical, thoracic, and lumbar vertebrae are there (2 points)? Q r r ‘. Us. WY: We» 5 ovug \ C t :17, \x 9 r W.) Luwvwr 3 g AH” (UQJA gwr L151. 0 L I 4,ch k r f » QM \QDW I 6‘54 KW) ‘ .: y \ ylhlklt ' Y I f ,w 3’ J "I quJerf-UN‘PXQI’M l Jc- 0‘. O gfa‘w\cw’\v a 5 5 - mt ‘ “9L " KOLQLC”) A!“ ‘r . . : SFIV‘DUL: ‘F 2 YR : w . ' \f\\/‘U:\vr:§—. 0 o ' \$MN£JWQA~F>€ 0‘ \ {0‘7 " CAL) \J) W w ’ NQO " ' ‘ we . Name 4. Given that the kinetic energy of a particle, T, is émvo v, show that the time derivative of T is 2F 0 v (4 points). \ cy’f 3 ( \ _, m — ( r M U" ”* “ s—» 2 / w M: “q” — w, \rvmv'i .ﬂmaau" w 2 we ”' W k I f b ~~~~~~~~~~~~~ ~ New”; 7 W“ W a9L7MVVQ ‘ d W649; J00“? mu < Name _ __ 5. During the pull stroke demonstrated below, determine whether each of the following joints ﬂex or extend: knee, hips, elbows. Which muscle groups are responsible for each motion? (5 points) Knee {7A LQWQQAA :5"? GDLL axJJri "‘ a §‘ ' l _ . ‘ 4 {gm/0,: m g) Who/h (1 11(4) ﬁLQ/y c7 ﬁll/oar? g f r e a ( http: / / www.crossfit.com / journal / library/ 50_06_Rowing_Technique.pdf Additional references at: http: / / www.culver.org / students / sports / crew/ rowingstroke.asp ...
View Full Document

{[ snackBarMessage ]}

### What students are saying

• 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.

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

• 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.

Dana University of Pennsylvania ‘17, Course Hero Intern

• 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.

Jill Tulane University ‘16, Course Hero Intern