Notebook 1DM - 1D motion (1)

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School

Iowa State University *

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Course

255

Subject

Physics

Date

Feb 20, 2024

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docx

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Uploaded by ChiefStraw12276

Lab 1DM - 1D motion Equipment  Motion detector  A cart that rolls on an aluminum track. The cart has an adjustable friction pad  Spirit level  Various masses, string and a pulley, to apply a force to the cart  A wood board (1" thick) that may be placed under the feet at one end of the track to tilt the track. The apparatus for this lab is depicted in the figure below. The string (when under some tension !) should be 162-164 cm long , including the loop at each end. Check its length by stretching it gently on the measuring jig, or use a meter stick. Adjust or replace it if necessary; string and scissors are available. Lab 1DM – Page 1

The cart and track  Handle and push the carts gently .  The two stops on the track (near the 20 cm mark and the 170 cm mark) prevent the cart from getting too close or too far from the motion detector.  The cart has a friction pad underneath it to produce friction if desired. Drag can be adjusted with the plastic screw located behind the reflecting plate. Please do not turn the screw all the way out. For today’s lab, the friction pad should be lifted so it does not touch the track. Is it lifted? Yes it is  Use the spirit level to check that the track is horizontal. Is this done? yes  Check now and several times during today’s lab that the track’s feet are not too close to the end of the table. The track tends to slide about. The motion detector The motion detector system measures the distance to the nearest object in front of the detector. It emits short bursts of sound of ultrasonic frequency and detects any reflections of this sound that come back. It measures the time between the emission of the burst and the first reflected sound (above some threshold level), and transmits this time information to the computer. From this, the computer software calculates the distance to the reflecting surface by using the known speed of sound (in air at room temperature). This process is similar to that used by some auto-focus cameras, as well as the echo- location process that bats use. The motion detector fills a cone-shaped region with sound. The motion detector will measure the distance to the closest object within that cone. The object that should reflect the first sound received by the motion detector is the plate on the cart; when you are pushing the cart, be sure that you and your hand are farther from the motion detector than the plate. "Bad" data points often are the result of an unwanted object being in the "cone" of sound. Lab 1DM – Page 2

1. Velocity, acceleration For this first part of the lab, the string and hanging weights should be put aside. The cart will be moved with your hands. Download and open 1DM – 1D motion.cmbl Do a quick test of the motion detector by moving the cart along the track. In the following activities, different motions will be described to you. For each case, the activity has 3 steps: a. Prediction: Sketch a qualitative prediction of the v-t and a-t graphs that correspond to that motion. b. Experimental result: move the cart accordingly (several times if needed until you obtain a satisfactory data set). Insert images of the graphs produced by the motion detector. c. Compare and discuss interesting qualitative features and differences of the predictions and the experimental results. These might be due to a variety of factors:  Imperfections of the experimental setup (try to specify what is the problem)  Bad experimental setup (wobbly or unleveled tracks, unwanted echoes, etc.)  Oversimplified or incorrect prediction. Lab 1DM – Page 3

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