PH 1140 Lab 1: Mass-Spring Oscillator I


Background

There are two parts to this experiment. In Part 1, you will measure the spring constant of two individual springs and then the spring constant of their series combination. In Part 2, you will measure the period of oscillation of two mass/spring systems, one with the series combination of two springs, and the second with one of the individual springs. In both parts you will have the chance to compare theoretically-predicted results with experimentally-determined values.

Procedure: Part 1

At your station there is a tall stand with a Vernier Dual-Range Force Sensor attached to a cross-bar located near the top. Make sure that the Force Sensor switch is set in the ±10 N position. There is also a Vernier Motion Sensor looking straight up at the Force Sensor from its position on the lab bench directly underneath the Force Sensor. Also at your station you should find two springs, a 50 g mass hanger, and several slotted masses (one 50 g and five 100 g).

Open the Single Spring Logger Pro template and zero the reading. Hang one of the springs from the hook at the bottom of the Force Sensor, and from the bottom end of the spring hang the mass hanger plus the 50 g slotted mass. IMPORTANT: Always handle the slotted masses so as NOT to drop them on the Motion Sensor below. Hold the slotted masses firmly until they are securely on the mass hanger, and if hooking or unhooking the hanger from the spring while slotted masses are on the hanger, be sure to cup your hand around the masses as well as the hanger.

Damp out all motion (side to side as well as up and down) of the hanger. When you are satisfied that it is stationary, collect data. Then Keep the data being recorded. Add a 100 g mass and stabilize the hanger again. Keep the data again, and repeat until you have a total mass of 600 g. After you keep the last data value, please be sure to Stop data acquisition. You can determine the spring constant with a least-squares linear fit. Be sure to record the slope in standard form. Repeat for the other single spring, calling it Spring 2.

Close the Single Spring template (completely close Logger Pro), and open the Series Spring template. Again, repeat the above with the pair springs in series. You may then proceed to part 2.

Procedure: Part 2

Now that you have determined the spring constants of two individual springs and their series combinations, the next step is to put a mass/spring system into oscillation so that you can compare the measured period of oscillation with the theoretically-predicted value.

Open the Oscillations template. Keep your spring set up as it is; most likely as the two in series, which is presumed in this lab. Re-zero this system. Decrease the mass on the spring to a total of 400 g. Set the system into oscillation by pulling the mass hangar down about 1 cm—not very far—and releasing it. Once you are satisfied that the mass/spring system is oscillating smoothly with little side-to-side motion, begin to collect data. Data is being collected by both the Motion and Force Sensors—the Force Sensor being smoother as it samples a rate more than 10 times that of the Motion sensor.

Once you have stopped data collection, you will want to try scaling the graph. Now, select the Force Sensor graph and place the cursor on right right-most peak so that you can read the time coordinate from the lower left portion of the graph. Find the time coordinate for the left-most peak as well- then record the time interval as well as the number of full oscillations between these peaks on your Data Sheet.

Repeat these steps for the single spring case (or for the other spring as well as both in series if you started with a single spring), and be sure that your data is clearly labeled for each case.

Files and Logger Pro Templates


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