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
Newton’s Second Law Lab Purpose: The purpose of this experiment was to determine the relationships between mass, force and acceleration as well as to prove Newton’s second law Hypothesis: It was hypothesized that there would be an inverse relationship between acceleration and mass; as the value of the mass increased the acceleration decreased. As well it is hypothesized that there would be a direct relationship between the net force and acceleration; as the net force increases the acceleration increases as well. Materials & Method: The materials that were required to do the experiment were a metre stick; its purpose was to measure the amount of string that is going to be used to drag the cart. Next equipment needed for the lab was a dynamic cart; it was going to be dragged by the string with a mass on the other end and will find relationships between these two. Also string (about 75cm) was needed in this experiment which would help pull the cart with the help of the masses that were used.
Experimental Design Focus question: What is the relationship between strain and time? Hypothesis: The more springs added, the mass will vibrate quicker. The more mass added, the longer it will take to vibrate. Vice versa, the more springs taken away, the longer the mass will take to vibrate. The more mass taken away, the quicker it will vibrate.
Usually the experimenter adjusts the direction of the three forces, makes measurements of the amount of force in each direction, and determines the vector sum of three forces. Forces perpendicular to the plane of the force board are typically ignored in the analysis. In order to complete this lab we used a force table, accessories, level,standard weights. And weight hangers. In order to complete the first lab we had to level the table and connect the rings to the pulleys.
The spring represents the elastic components of the muscle and obeys Hook’s law : F=k*x but in terms of stress the equation turns into : σ=Ε*ε where σ: applied stress, E:Young's Modulus of the material ε: strain. The dashpot represents the viscous components of the muscle and is expressed in differential form by Newton’s law for straight,parallel and uniform flow: σ=η* where η: viscosity and :change of rate of strain (velocity). The important equations that are used in this model are: F=F1+F0 where F0=k0*u and F1=η1*u1=k1*u1’ u=u1+u1’ After long calculations we finally take the differential equation of motion for a standard linear solid: The equation contains F, df/dt ,u ,du/dt functions as well as k0,k1,η constants and is impossible to solve as they are all unknown. For that reason we will use the experimental data from Bobsbooms given paper that will help understand how our functions are supposed to behave during the experiment and thus be able to extract some data and some important initial and boundary conditions, necessary for our model to work. From the Bobsbooms paper ‘Passive transverse mechanical properties of skeletal muscle in compression’ we are supposed to take the ramp and hold data (u versus t graph) and fit it in our model,expecting that our F versus t
The purpose of this experiment was to measure centripetal acceleration and a centripetal force of a mass. The mass was then hung on an apparatus and attached to a spring. The mass was then rotated. The centripetal force was calculated using measurements of radius of the path, the time it takes to revolve around that path, and the mass. Procedure The group first took measurements such as the mass of the object, the radius of the rotation, the tension of the mass when we attached it to the apparatus.
1 of 22 Investigation of Deflection of a Cantilever vs. Length of a Cantilever Research Question How does the length of a cantilever affect the deflection of that cantilever when loaded with a constant mass? Introduction The purpose of this lab is to investigate the deflection of a cantilever. In this investigation, I chose to measure the effect of the length of a cantilever on its deflection when loaded with a constant mass because I knew from prior experience that there was some relationship between the two variables. The objective of this investigation is therefore to establish a relationship between the length of a cantilever and its deflection in the aforementioned situation, which may give some insight into the physics of cantilevers.
m_2 a=m_2 g-T T=m_2 g-m_2 a Equating the tensions m_1 a=m_2 g-m_2 a m_1 a+m_2 a=m_2 g (m_1+m_2 )a=m_2 g a=(m_2 g)/(m_1+m_2 ) The acceleration is the same acceleration described in the kinematics equation a=2s/t^2 For a body starting from rest, s is the distance traveled by the cart and t is the time of travel. We had objectives to meet by the end of the experiment. First of which was to verify the direct proportionality of acceleration and net force if the mass of the body is constant. Meaning, if the acceleration value increases, the net force of the mass must increase as well, given the fact that the mass of the body is constant. The second is to verify the inverse
If true stress is plotted against true strain, the rate of strain hardening tends to become almost uniform, that is, the curve becomes almost a straight line [2]. The strain hardening coefficient of work is defined as the gradient of the straight part of the line. This is closely related to the shear modulus [2]. Therefore, a metal with a high shear modulus will have a high strain or work hardening coefficient. Grain size will also influence strain hardening, and a material with small grain size will strain harden more rapidly than the same material with a larger grain size.
P2 Fitness test for the main components of fitness There are 8 components of fitness which are, cardiovascular endurance, strength, muscular endurance, flexibility, speed, reaction time, agility and coordination. 1. Cardiovascular endurance This is also known as an aerobic endurance or stamina, which is the ability to repeat an activity for a length of time without becoming tired. A fitness test for this component is the cooper or bleep test. Cooper Test/Beep test Cardiovascular endurance can tested for by using various maximal tests which test your limit of endurance in some exercise .