🏷️ LIMITED TIME OFFER: GET 20% OFF GRADE+ YEARLY SUBSCRIPTION →
Log in
HomeClass Notes1,200,000CA670,000

Kinesiology 2241A/B Lecture Notes - Lecture 9: Net Force, Angular Velocity, Muscle Contraction

11 views2 pages
School
Western University
Department
Kinesiology
Course
Kinesiology 2241A/B
Professor
Daniel Bechard

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

Document Summary

Power: is proportional to force and velocity o o o o. There is a trade off between force and velocity. If you can produce a lot of force very quickly then you are very powerful. You can also either provide a lot of force slowly or a low force but very quickly: as you close the angle of your elbow, you are able to improve the amount of force production. The smaller the angle between arm and forearm, the more force the bicep can produce up until 90. You can lift the most weight with your elbow at 90. As you close the angle even more, the force you are able to produce from this becomes smaller once again o. The zero point is isometric, to the right is contracting and the left is extending the muscle (trying to contract but cannot hold it). Where the line crosses zero is the maximum isometric force.

Get access

Grade+20% off
$8 USD/m$10 USD/m
Billed $96 USD annually
Grade+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
40 Verified Answers
Class+
$8 USD/m
Billed $96 USD annually
Class+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
30 Verified Answers

Related Documents

Kinesiology 2241A/B Lecture Notes - Lecture 9: Angular Acceleration, Net Force, Kinetic Energy
browncoyote548
Kinesiology 2241A/B Lecture Notes - Lecture 6: Sacral Plexus, Brachial Plexus, Cervical Plexus
coffeegrasshopper525
Kinesiology 2241A/B Lecture Notes - Lecture 25: Myocyte, Ligament, Modulus Guitars
jadeporpoise270

Related Questions

A person exerts a horizontal force of 190 N in the apparatus shown in the figure (which you cannot see but I'll explain). Find the horizontal force M that his flexor muscle exerts on his forearm. Picture a person's right arm flexed at what appears to be 90 degrees. Flexor (bicep) muscle of upper arm has M running through it horizontally along the x-axis and arrow head points to the left, towards person's face. From humerus bone (underneath bicep) up to wrist level is 0.34 m, along y-axis.....which if you follow it to the right, you'll end up at the elbow joint, labeled. From middle portion of elbow joint to middle portion of radius (forearm bone on thumb side) is 0.054 m. This amount takes up a spot on the y-axis, along the very bottom part of it. The 190 N is labeled to the right of the person's wrist but there is no arrow head denoting which way the force is directed.

I would appreciate help with any of the following problems. Thankyou.

22. In an isometric exercise a person places a hand on a scale andpushes vertically downward, keeping the forearm horizontal. This ispossible because the triceps muscle applies an upward forceperpendicular to the arm, as the figure indicates. The forearmweighs 22.1 N and has a center of gravity as indicated. The scaleregisters 113 N. Determine the magnitude of .
Distance between the force applied by the muscle and the elbowjoint 0.025 m. The distance between the elbow joint and the armscenter of gravity is 0.15 m. Distance between the arms center ofgravity and the center of the scale is 0.15 m. I was not able tofind the answer to this problem using the solution posted on thewebsite.

26.A wrecking ball (weight = 4310 N) is supported by a boom, whichmay be assumed to be uniform and has a weight of 2550 N. As thedrawing shows, a support cable runs from the top of the boom to thetractor. The angle between the support cable and the horizontal is32°, and the angle between the boom and the horizontal is 48°. Find(a) the tension in the support cable and (b) the magnitude of theforce exerted on the lower end of the boom by the hinge at pointP.

56. Two identical wheels are moving on horizontal surfaces. Thecenter of mass of each has the same linear speed. However, onewheel is rolling, while the other is sliding on a frictionlesssurface without rolling. Each wheel then encounters an inclineplane. One continues to roll up the incline, while the othercontinues to slide up. Eventually they come to a momentary halt,because the gravitational force slows them down. Each wheel is adisk of mass 3.64 kg. On the horizontal surfaces the center of massof each wheel moves with a linear speed of 5.26 m/s. (a),(b) Whatis the total kinetic energy of each wheel? (c), (d) Determine themaximum height reached by each wheel as it moves up the incline. Iwas able to solve for the rolling wheel but couldn't find the rightanswers for the sliding wheel.

66. A thin uniform rod is rotating at an angular velocity of 1.89rad/s about an axis that is perpendicular to the rod at its center.As the figure indicates, the rod is hinged at two places,one-quarter of the length from each end. Without the aid ofexternal torques, the rod suddenly assumes a "u" shape, with thearms of the "u" parallel to the rotation axis. What is the angularvelocity of the rotating "u"?

76. A woman who weighs 501 N is leaning against a smooth verticalwall, as the drawing shows. Find (a) the magnitude of the force N(directed perpendicular to the wall) exerted on her shoulders bythe wall and the (b) horizontal and (c) vertical components of theforce exerted on her shoes by the ground.

On Amazon.com, there are three versions of Keynes' famous General Theory: a hardcover for $19.79, a paperback for $8.82, & a Kindle version for $2.99. There is not much difference in the cost of production between hardcover & paperback books (there likely is for the Kindle e-book version), but hardcover books do tend to be published earlier than paperback versions of the same book.

How do you explain the wide variety of prices for basically the same book?

A. Even though the cost of production between hardcover and paperback is small, demand is highly elastic, so this small cost difference results in a large price difference. The cost difference between paperback and e-books is larger, resulting in the smaller gap between paperback and e-book prices.

B. The market for hardcover books has more demand and less supply than the market for paperbacks, which likewise has more demand and less supply than the market for e-books. The equilibrium prices all reflect these differences.

C. Price discrimination between demanders. High demanders are willing to pay a high price for a hardcover that is published early. Low demanders aren't, and are only willing to pay a low price for the later paperback. It is much cheaper to produce the Kindle version (MC probably close to zero), and not many buyers (people with Kindles, less D) lead to the lowest price.

D. Price discrimination between demanders. Kindle owners are high demanders since the format is not compatible with anything but Kindles. Hardcover buyers are low demanders since there aren't many who would want a hardcover when paperbacks or e-books are cheaper. There are more paperback buyers, so they pay a price between these two extremes.