Possible Work and Energy lab

# Possible Work and Energy lab - Experiment Work and Energy...

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Experiment 18 Work and Energy Work is a measure of energy transfer. In the absence of friction, when positive work is done on an object, there will be an increase in its kinetic or potential energy. In order to do work on an object, it is necessary to apply a force along or against the direction of the object’s motion. If the force is constant, work can be calculated using the vector dot product where F is the constant force and s the displacement of the object. If the force is not constant, we divide the overall displacement into short segments, s , the force is nearly constant during each segment. The work done during that segment can be calculated using the previous expression. The total work for the overall displacement is the sum of the work done over each individual segment: This sum can be determined graphically as the area under the plot of force vs. distance. 1 These equations for work can be easily evaluated using a force sensor and a Motion Detector. In either case, the work-energy theorem relates the work done to the change in energy as W NC = U + K where W NC is the work done (by non-onservative forces), U is the change in potential energy, and K the change in kinetic energy. In this experiment you will investigate the relationship between work, potential energy, and kinetic energy. OBJECTIVES Use a Motion Detector and a force sensor to measure the position and force on a hanging mass, a spring, and a dynamics cart. Determine the work done on an object using a force vs. distance graph. Use the Motion Detector to measure velocity and calculate kinetic energy. Compare the work done on a cart to its change of mechanical energy. Test the Conservation of Mechanical Energy Principle. MATERIALS Power Macintosh or Windows PC dynamics cart Vernier Motion Detector masses (200 g and 500 g) Vernier Force Sensor spring with a low spring constant (10 N/m) Universal Lab Interface Tape and rubber band 1 If you know calculus, you may recognize this sum as leading to the integral . Physics with Computers 18 - 1

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Experiment 18 Logger Pro wire basket (to protect Motion Detector) PROCEDURE Part I Work When The Force Is Constant In this part you will measure the work needed to lift an object straight upward at constant speed. The force you apply will balance the weight of the object, and so is constant. The work can be calculated using the displacement and the average force, and also by finding the area under the force vs. distance graph. 1. Connect the Vernier Motion Detector to PORT 2 and the Vernier Force Sensor to DIN 1 of the Universal Lab Interface. 2. Open “Exp18DRA” from the Physics with Computers experiment files of Logger Pro. Set the range switch on the sensor to 10 N. Three graphs will appear on the screen: distance vs. time, force vs. time, and force vs. distance. Data will be collected for 5 s. 3.
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Possible Work and Energy lab - Experiment Work and Energy...

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