HKIN 298 TWU Biomechanics Torque Levers Balance and Stability Assignment

User Generated

abababababa

Science

HKIN 298

Trinity Western University

HKIN

Description

the course is for biomechanics based on textbook called applied biomechanics concepts and connections chapter 6, chapter 8 and chapter 7please make sure to used full sentences, show all the work and explain the reasoning

Unformatted Attachment Preview

HKIN 298 Biomechanics Chapter 6/8 Torque and Levers. Chapter 7 Balance and Stability. Questions. (21.5marks) Please type directly into the MS Word doc in BOLD script, please. Use full sentences. For calculations, show your work. 1. Two athletes perform shoulder dumbbell raises (arms straight from the side, abducted to 90 degrees) with 15 lb dumbbells. One athlete has much longer arms than the other. Explain biomechanically why the shoulder raise for the athlete with the longer arms demands more muscular force than for the athlete with shorter arms as he rotates his arms to 90 degrees to the ground. (2 marks) 2. Describe fully what the two key functions of levers are (2 marks). 3. Two children wish to balance on a 2.5 m long teeter-totter. One child has a weight force of 80N and sits 1.6m from the axis. The other child has a weight force of 90N. How far from the axis does the second child have to sit from the axis to balance the teeter-totter? Show your work (1 mark) 4. The length-tension relationship is in (skeletal) muscle helps us understand force variation in human muscle across a range of motion. In a couple of sentences, describe the length-tension concept in your own words (2 marks) 5. With respect to the length-tension relationship in muscles, explain what ‘active insufficiency’ is (1 mark) 6. The following diagram shows a series of base of supports (1-3), each receiving an external force (A and B). Which of the following base of supports would be the most stable and least stable receiving: 1. External force A? 2. External force B? E.g. BOS 1 would be most stable receiving force ___ because….but least stable receiving force ____ because… Give a reason for your answer (2 marks) 7. The following is a graph of the force velocity relationship. In your own words (don’t copy and paste from the powerpoint) describe briefly what this relationship is (2 marks) 8. In the following diagram if the motive force was 40N and the motive force arm was 0.3m and the resistive force was 10N and the resistive force arm was 0.8m, calculate the net torque and direction of this system. Show your work (1 mark) . Motive force Resistive force 9. For the following diagram label each position from least stable to most stable using the following anchors: (2 marks) 1 = least stable 2 = somewhat stable ______ 3 = more stable _______ 4 = most stable _______ ______ 10. Label each of the following diagrams as either 1st class lever, 2nd class lever or 3rd class lever (1.5 marks) Where M = motive force, R = resistive force and A = axis ____________________ _____________________ _____________________ 11. The following is a diagram of a knee extension exercise showing the femur (solid triangle), knee joint or axis (solid dot), kneecap (oblong circle) and two positions of the lower leg (A – beginning extension and B – end of extension). The dotted line arrows represent the lines of resistive weight force of the lower leg at positions A and B. The solid arrow represents the average location of the line of motive muscle force exerted by the quadriceps muscle as the lower leg moves from position A to B. Answer the following questions: (a.) Describe the differences between the average muscle motive force arm and the resistive force arms of the lower leg. What changes to the size of the resistive and motive force arms do you see occurring as the lower leg moves from position A to position B (towards full extension)? (2 marks) (b.) The resistive force of the lower leg is 100N. The size of the resistive force arm at A is 0.1m and at B it is 0.22m. If the average muscle force arm is 0.02m, calculate the amount of muscle force needed to rotate the lower leg at both A and B. (1 mark). B A 12. Why is it more difficult to open a door as you push closer to the hinges compared to further away from the hinges? Describe how the lever models change as you move points of force application closer to the hinge (axis). Does the resistive torque change as force is applied closer to the axis? Why or why not? (2 marks)
Purchase answer to see full attachment
User generated content is uploaded by users for the purposes of learning and should be used following Studypool's honor code & terms of service.

Explanation & Answer

Find the attached solution .....Do let me know if you need any revision/edits.... and invite me for future assignmentsGood bye for now ...See you buddy ...

HKIN 298 Biomechanics
Chapter 6/8 Torque and Levers. Chapter 7 Balance and Stability. Questions. (21.5marks)
Please type directly into the MS Word doc in BOLD script, please. Use full sentences. For
calculations, show your work.
1. Two athletes perform shoulder dumbbell raises (arms straight from the side, abducted to 90 degrees)
with 15 lb dumbbells. One athlete has much longer arms than the other.
Explain biomechanically why the shoulder raise for the athlete with the longer arms demands more
muscular force than for the athlete with shorter arms as he rotates his arms to 90 degrees to the ground.
(2 marks)

The force applied by the athlete is translated to torque exerted at the joint. This is the reaction force
at the joint. Since the weight carried by the athlete is same, the torque exerted at the joint is
proportional to the arm length.
The torque exerted at the joint is T = F x r. Now F is constant for both cases, but arm length r is small
for shorter armed athlete. So, the effort required by the athlete with longer arm is more.

2. Describe fully what the two key functions of levers are (2 marks).

A lever is used to amplify the input force and acts around the pivot. In a human body, the lever is
usually the bone and the pivots are joints. This is strength advantage of the lever. The mechanical
forces are applied by the muscles.
The next function of the lever is related to the movement advantage about pivot. This changes the
speed and range of motion. In the case no advantage in form of amplified mechanical force is
obtained.
Thus, there are two function of levers which are amplification of force and the advantage of
movement. At any time, the lever can provide only one function

3. Two ch...


Anonymous
I was having a hard time with this subject, and this was a great help.

Studypool
4.7
Trustpilot
4.5
Sitejabber
4.4