1. Procedure: 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. Equipment Setup: A force sensor is connected to "CH 1" and a motion detector is connected to "DIG/SONIC 1" of the Vernier LabPro interfaced. The range switch on the force sensor is set to 10 N. Computer software for data collection is the LoggerPro software loaded with "WorkEnergy" experiment. Notice three graphs are being used of: distance vs. time, force vs. time, and force vs. distance.
2. Place the Motion Detector on the floor, away from table legs and other obstacles. Be extra cautious during this experiment not to drop weights onto the detector. Hang a 200g mass from the Force Sensor.
3. Hold the Force Sensor and mass about 0.5 m above the Motion Detector and click "Start" to begin data collection. Wait about a second after the clicking sound starts, and then slowly raise the Force Sensor and mass about 0.5 m straight upward. Then hold the sensor and mass still until the data collection stops at 5 s.
Try this a few times till you feel you have a set of data representative of your experiment.
4. Sketch the three graphs into your notebook
5. Examine the distance vs. time and force vs. time graphs by clicking the Examine button . Identify when the weight started to move upward at a constant speed. Record this starting time and height in a data table and on your sketched graph
5. Examine the distance vs. time and force vs. time graphs and identify when the weight stopped moving upward. Record this stopping time and height in a data table and on your sketched graph.
6. Determine the average force exerted while you were lifting the mass. Do this by selecting the portion of the force vs. time graph corresponding to the time you were lifting (refer to the position graph to determine this time interval). Do not include the brief periods when the up motion was starting and stopping. Click the Statistics button, to calculate the average force. Record this value in your data table.
7. On the force vs. distance graph select the region corresponding to the upward motion of the weight. (Click and hold the mouse button at the starting distance, then drag the mouse to the stopping distance and release the button.) Click the Integrate button to determine the area under the force vs. distance curve during the lift. Record this area in the data table.