LABORATORY REPORT Activity: Recruitment and Isotonic and Isometric Contractions Name: Carolyn Chrzastowski Instructor: Professor Waite Date: 07.19.2015 Predictions When the arm goes from resting to flexing, the amplitude and frequency of sEMG spikes will increase During flexion, the amplitude and frequency of sEMG spikes will ___ during extension. be greater than Recruitment of motor units will be greatest when the load is 20 pounds Materials and Methods Comparison of motor unit activation during muscle tone and concentric and eccentric isotonic contractions Dependent Variable amplitude and frequency of sEMG spikes Independent Variable muscle movement Controlled Variables total number of motor units
Description and Theories A. Principles and Theories Used to Obtain our Result An conventional spring, when subjected the weight (w=mg) of an object at one of its terminations, will displace a certain distance, x, with an equal and opposite force, F, being created in the spring of which opposes the pull of the weight. This conventional spring will become significantly distorted if it is subjected to a large enough weight and the force, F, will only be able to return the spring to its original configuration once the burden is removed. The force that will restore the spring to its original configuration is directly proportional to the displacement that occurred. The following equation represents this relationship where k denotes the spring constant or stiffness of the spring, F=-kx Since x symbolizes the displacement or change in the length of the spring the above equation can now be surmised in the following manner, F=mg=-k∆l This new form makes it evident that a linear proportion exists between the plot of F as function of changing in length, ∆, thus confirming the spring does in fact obey Hooke’s Law.
a. decreasing the temperature b. changing the concentration of A c. changing the concentration of B d. changing the concentration of C e. letting the reaction go on for a long time 4. The gas phase reaction A + B C has a reaction rate which is experimentally observed to follow the relationship rate = k[A]2[B]. If the concentration of A is tripled and the concentration of B is doubled, the reaction rate would be increased by a factor of ____. a. 6 b.
Unit 2 Acute response to exercise is short term effects that exercise has on the body. Musculoskeletal response An acute response of the musculoskeletal system during exercise includes an increase in blood supply. The short term effects on your muscles increases the temperature therefore there is more activation energy so chemical reactions are used by the musculoskeletal system and the metabolic activity increases. As the oxygen demand increases, more oxygenated blood needs to be supplied to the muscles so vasodilatation occurs so more blood can pass through the arteries. This affected me during the bleep test because vasodilation allows more oxygenated blood to travel to the actively respiring muscle tissues.
28 October 2008 Introduction: Static and kinetic friction are forces that are a result of two surfaces in contact with each other. Static friction is the force that must be overcome to cause an object to begin moving, while kinetic friction occurs between two objects in motion relative to each other. The kinetic friction force, Ff, kinetic, is defined by Ff, kinetic = μkFN, where μk is the coefficient of kinetic friction and FN is the normal force acting on the object. The maximum static frictional force Ff, max static, is defined by Ff, static = μsFN where μs is the coefficient of static friction and FN is the normal force on the object. The maximum frictional force that must be overcome before movement is able to begin is μsFN.
According to Dowding (1988) two levels of analysis can be considered. The first level of analysis (pseudo-static) involves the addition to the sliding mass of an inertial force that is equivalent to the anticipated acceleration times the mass. The next level considers the slope as a rigid block that slides in response to the base motion. Both these traditional analytical techniques have
|Resistance |Effort | |Force, as added mass |Arm length |Work |A |B |Total force |Arm length |Work | |to resistance side (g)|(m) |(N × m or J) |Force (N) applied |Pulling force applied |B-A |(m) |(N × m or J) | |converted to (N) | | |to balance the |to the spring scale | | | | | | | |lever with no mass|(n) when mass is added| | | | | | | |on effort side |to effort side | | | | |300 g = |0.70 |2.058 |0.87 |22.74 |21.87 |0.40 |8.748 | |2.94 N | | | | | | |
An object accelerates if its velocity is constantly changing, also known as speeding up or slowing down. If an object is accelerating then it is not in equilibrium. Equilibrium is when all the forces action on an object are balanced, thus all the forces cancel out and the object is not moving or is moving at a constant rate. Since gravity is present in this lab the objects will never be in equilibrium. The objects will always be moving at a constantly
An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force. This law is called the law of inertia. The second law stated that acceleration is produced when a force acts on a mass. The greater the mass, the greater the amount of force needed. This law was referred to as force equals mass times acceleration.