Log in
HomeClass Notes1,200,000CA670,000

Kinesiology 3341A/B Lecture Notes - Lecture 10: Acceleration, Angular Acceleration, Angular Displacement

80 views4 pages
School
Western University
Department
Kinesiology
Course
Kinesiology 3341A/B
Professor
Jim Dickey

For unlimited access to Class Notes, a Class+ subscription is required.

Document Summary

Midterm is in class on monday after ouas. Lab: the arrows are at specific points in time. A force/time curve showing the ground reaction forces so they are the forces being applied back to the athlete, not the forces applied to the board. A force is only composed of mass and acceleration, therefore if you do not have one of them then you do not have a force. Think of the right hand rule in order to orient yourself to the lines on the curve. Typically, z is + up and y is + to left and x is + forward. Up to me to determine whether this is true for this graph. The key thing with q2, just make a 2d simple system and label the forces in only the plane shown. The bike and the cyclist are one system and you must treat them this way.

Get access

Grade+
$40 USD/m
Billed monthly
Grade+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
10 Verified Answers
Class+
$30 USD/m
Billed monthly
Class+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
7 Verified Answers

Related Documents

Kinesiology 2241A/B Lecture Notes - Lecture 7: Ground Reaction Force, Kinematics, Free Body
carminecheetah358
KNES 300 Lecture 12: Linear Kinetics II
orangereindeer556
Kinesiology 2241A/B Lecture Notes - Lecture 6: Net Force, Ground Reaction Force, Kinematics
bluetiger638

Related Questions


1) A stepladder (shown in figure 12-52 on page 325 in your book)has sides which are each 3.0m long and hinged at the top. A 0.8mtie-rod is located half way up. A man weighing 800N climbs 2.1malong the ladder’s length. So that we’re all using the samevariables, let us define
W= 800m L=0.3 m d=1.2m s=8.0
Assuming that the floor is frictionless and neglecting the mass ofthe ladder …
(0.5 points)
Write an expression for the angle that the ladder makes with thehorizontal.

Model the situation with Newton’s Second Law [and its rotationalequivalent]. Set up the system of equations as if you were to solvefor the quantities below. You equations should be in terms of thevariables given above only (no numbers) and trig functions of theangle above (just call it ).

One last comment; in addition to the forces below, there’s one more(your job to figure out what it is) that will be in your equations.The force has components. Tip: Rather than defining a new angle andmessing with more trig functions, just call the x-component Fx andthe y-component Fy in your equations.

solve the above equations for the following quantities (give me anexpression in terms of the variables first, then give me the actualnumber)…
(1 points)
a) The tension in the tie-rod. (Call it T in your free-bodydiagrams and equations.)
The magnitude of the force on the ladder from the floor on;
(1 points)
b) the left side of the ladder (where the person is)? (Call it FLin your FBDs and your equations.)
(1 points)
c) the right side of the ladder? (Call it FR in your FBDs and yourequations.)
***Remember to draw free body diagrams (for yourself, not to besubmitted) and write out all equations using variables before youplug in numbers. Also notice that the numbers in your book areslightly different than those in this problem, but the book’sanswer should provide you a way to check your method andsolution.

What is the difference between the study of kinematics and kinetics in regard to forces?

What three components that make up the musculoskeletal “system”.

The musculoskeletal system is composed if many simple machines. There are 4 potential uses for these simple machines, list 2 of these uses.

Fill in the blank a _________ is used to alter the resulting direction of the applied force.

In the body what component acts as a lever and what acts as the axis?

When we think of a lever set up, what does FAR refer to?

Draw a basic F.A.R for each of the following and give an example of where in the body you may find each.

First class lever:

Second class lever:

Third class lever:

Which class of levers is designed best for speed and range of motion and which is best for strength?

What forces determine amount of torque in a system?

A. How much torque needs to be produced to move 60 kg (R) when the RA is 0.30 m and the FA is 0.1 meters?

b. What value could you change to decrease the torque needed to lift the SAME object.

c. Draw the F.A.R unit (say an arm lifting a bucket) label the elements and explain why what you changed in b would decrease torque needed.

12. a. What is the “contractile” unit of muscle called? ______________

b. what is the non-contractile element (series elastic element) in a muscle lever system?

13. in regards to “power” which is more powerful, muscle fibers arranged in Parallel or bipennate muscles? ___________

Why?

14. When weight lifting with the goal of increasing strength, what physical characteristic of the muscle are you changing to bring about that increased strength? __________________

15. What is the branch of FDA that controls regulation of medical devices? ____________

16. Which of the following statements is false?

A device can be an instrument or an apparatus.

A device can be something used to diagnose a disease

A device can change the chemistry of your cells

A device can be something that delivers a drug to your body

17. Give one example of a..

Class I device

Class II device

Class III device

18. Which of the following is true regarding device classification?

Devices with the least risk to the patient are considered Class III

A class III device has a high risk potential to the patient

Class III devices are the easiest to get approved

Testing devices on humans is easy and follows no specific guidelines

19. Explain the difference between Harm and Risk.

20. What is a “substantial equivalent”? Is it easier or harder to get approval for a Device that has an SE?

21. Which of the following would not be a priority when developing a medical device?

Cost

Ergonomics

Ease of sterilization

Material

None of the above

1. Why Niall Ferguson thought that the expansionary fiscal policy (or government deficit) could produce crowding-out effect? You can explain by using the IS-LM model or you can use the logic of loanable funds theory

Answer: Ferguson believes that an increase in the government deficit could produce a crowding-out-effect. First, I will touch base on fiscal policy. Well, what is it? Basically, it adjusts the nation’s spending amount which increases the economy’s deficit to close a recessionary gap, which therefore increases the the demand for loans, meaning people want to borrow money. An increase in demand for loans leads to an increase in interest rates. Higher interest rates lead to a decrease in investment and interest-sensitive consumer spending, so both C and I decrease. That’s what the crowding-out-effect is, the decrease in investment due to higher interest rates.

>in Deficit = >in Demand for Loans = >in interest rates =

The government speeds up the economy by deficit spending, they crowd out consumers and investors with high interest rates. So what this means is that the government is attempting to help the economy but it is actually hurting the economy. The reason why I think Ferguson believes this is because of what he says in his debate at the New York Review of Books, that “you can’t be both a monetarist and a Keynesian simultaneously—at least I can’t see how you can, because if the aim of the monetarist policy is to keep interest rates down, to keep liquidity high, the effect of the Keynesian policy must be to drive interest rates up.” He continues on in the interview to say that the Fed has minted out a fresh $1.75 billion in bonds and that no one is going to buy them. Driving up bonds will increase interest rates which increases mortgage rates which is why he basically doesn’t agree with the Keynesian theory.

2. Why Paul Krugman thinks that Niall Ferguson was wrong and thought that government deficit could not produce a crowding-out effect? In other words, please explain Krugman's Liquidity trap .

Answer: To start I think Krugman believes that the Fiscal policy is effective. It is effective when the Liquidity-Money (LM) curve is horizontal. It creates the crowding in effect. The supply of money is constant so it creates money demanded to be interest inelastic, meaning it doesn’t change. So if the government wishes to stimulate the economy, it leaves interest rates at a constant rate, and an increase in investment and saving, therefore helping the economy close the gap on a recession. There is an indifference between money and bonds so this makes fiscal policy effective. So then we get into a monetary expansion, meaning we have an increase in the money supply. Well with the liquidity trap, we get the case that the investment-savings (IS) curve is horizontal. So when the government increases the money supply, investment responds to rapidly changing interest rates, which would decrease the money demanded, making monetary policy effective. But the liquidity trap becomes apparent because interest rates cannot fall below zero percent. This is when monetary policy would become ineffective because interest rates aren’t declining meaning investment wouldn’t continue. Krugman in his blog basically argues this. He states “Most spectacularly, IS-LM turns out to be very useful for thinking about extreme conditions like the present, in which private demand has fallen so far that the economy remains depressed even at a zero interest rate.” He sums up his argument for the liquidity trap and explains his logic behind the investment-savings, liquidity-money curve, and that is why he disagrees with Ferguson.

3. In the discussion, other discussants such as George Soros and Robin Wells pointed out some interesting issues. Please provide at least one thing that you agree and one thing that you disagree. Discuss in details why you think so.

Answer: One thing I found interesting was George Soro’s point in the debate in the New York review of books. He states “The other feature is that the financial system collapsed of its own weight. That contradicted the prevailing view about financial markets, namely that they tend toward equilibrium, and that equilibrium is disturbed by extraneous forces, outside shocks. Those disturbances were supposed to occur in a random fashion. Markets were seen basically as self-correcting. That paradigm has proven to be false. So we are dealing not only with the collapse of a financial system, but also with the collapse of a worldview.” He continues to mention how Obama has 2 problems he has to face and how people who are viewing this crisis the same as the previous financial crisis, are making a huge mistake. To explain he states this: “But when you have a collapse of credit there’s only one source of credit that is still credible, and that’s the state: the Federal Reserve and the Treasury. Then you have actually to inject a lot more leverage and money into the economy; you have to print money as fast as you can, expand the balance sheet of the Federal Reserve, increase the national debt. And that is, in fact, what has been done, which is the right thing to do. But then once this policy is successful, you have to rein in the money supply as fast as you can.” I think Soro is agreeing with Krugman and the monetary policy of pumping money into the economy. It will raise the money supply which eventually is left for us to capitalize on supply and let our GDP. Now I find this interesting because he is also agreeing with Krugman’s IS-LM model, and later on, we come to find out that even Ferguson had come to an agreement with Krugman’s points, with the exception being that the United States was a powerhouse, and therefore the European Union would eventually see its downfall.

Please make comments to the answer of discussion I provided above(at least 300 words total). And you can start with "I agree with you on some points... But I disagree with you on some points".