LABORATORY REPORT Activity 2: Twitch Contractions and Summation Name: Instructor: Date: PREDICTIONS Effect of Muscle Fiber Length on Contraction 1. As muscle fiber length increases: Effect of Stimulation Frequency on Contraction 2. As the frequency of stimulation increases, the force of contraction: MATERIALS AND METHODS Measurement of Threshold Stimulus 1. Dependent Variable 2. Independent Variable 3.
A straight line approximation for the Mohr-Coulomb failure envelope can then be drawn. The friction angle is thus calculated from the slope of the failure envelope. As with any experiment, the more tests taken for different normal stresses, the more accurate the Mohr-Coulomb failure envelope will be. Experimental Procedure * Weigh the initial mass of soil and record it. * Measure the height, width and length of the shear box and record it.
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. This enabled the group to determine the spring constant k. B. Derivation of Equations Definitions To gain a better understanding of the terms used here
LABORATORY REPORT Activity: Name: Instructor: Date: Twitch Contractions and Summation Predictions Effect of Muscle Fiber Length on Contraction 1. As muscle fiber length increases contraction force decreases Effect of Stimulation Frequency on Contraction 2. As the frequency of stimulation increases, the force of contraction: increases Materials and Methods Measurement of Threshold Stimulus Dependent Variable contraction force Independent Variable stimulation voltage Controlled Variables temperature, frequency of stimulation, muscle fiber length Effect of Muscle Length on Contraction Dependent Variable contraction force Independent Variable muscle fiber length Controlled Variables temperature, stimulation voltage, frequency of stimulation Effect of Stimulation Frequency on Contraction Dependent Variable contraction force Independent Variable frequency of stimulation Controlled Variables temperature, stimulation voltage 4. What structure was stimulated to cause a muscle contraction? The motor unit was stimulated 5.
The contractile unit consists of myofibrils which encompass repeating units of sarcomeres running end to end giving a striated appearance to the muscle. Each sarcomere is characterized by two z-lines, one M-line, an A-band and an H-zone. Actin and myosin are the principle proteins in the contractile machinery with myosin dominating the A-band. The latter refracts plane polarized light (anisotropy) giving a dark appearance to
The Muscular System: Sliding Filament Theory 1. a. The thick filament is composed of what molecule? __________Myosin_____________ b. Flexing the head of this molecule provides what is known as the ________Power Stroke_________________. 2. The myosin head contains binding sites for what two molecules?
Experiment 1: Pressure, Temperature, and Velocity Measurement Objective: The objective of this experiment is to determine the pressure and density of laboratory air, calibrate a pressure transducer and scannivalve, then determine the test section speed as a function of fan speed using three methods of velocity measurement. Equipment: Absolute pressure transducer, digital thermometer, pressure transducer (voltmeter), micromanometer, scannivalve, Pitot tube, low-speed wind tunnel. Part 1: Measurement of Atmospheric Pressure and Density 1. Read the barometer and wind-tunnel thermocouple. 2.
| |[pic] |For movement we require skeletal muscles to contract for force and power production. | | |The intensity and duration of the exercise will determine the type of muscle fibres recruited and | | |the force and frequency of the contraction. | | |Type I muscle fibre: Slow twitch. | | |Type II muscle fibre: Fast twitch. | | |Average person has equal amounts of Type I and Type II.
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
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.