1. What effect does changing the mass on the spring have on the frequency of the spring? Why do you think this is true? (Both explain and back it up with numbers from your experiment!)

2. What effect does changing the displacement of the mass on the spring have on the frequency? Why do you think this is true? (Both explain and back it up with numbers from your experiment!)

3. By stretching the spring further, you are giving it more energy. By adding more mass, you are giving it more inertia. Using these ideas, explain the results of this investigation. (Explain what you witnessed and have concluded, and back up your comments with data from your experiment.)

4. If a pendulum completes 40 vibrations in a minute, what is its period?

5. Describe a vibration that is not periodic.

Introduction A periodic motion is any motion that repeats regularly. One example of a periodic motion is vibration. Vibrations are created when systems oscillate between two high energy states. One example of vibration is a mass on a spring. A mass on a spring is subject to two opposing forces, one constant and one variable. The constant force is the force of gravity, which acts downward with a magnitude equal to the weight of the mass. The variable force is the restoring force of the spring, which acts upward with a force that is proportional to the amount that the string has been stretched from its equilibrium point. The high energy state for gravitational energy is when the mass is at its highest point. The high energy state for the elastic potential energy ofthe spring is when the mass is at its lowest point. This conguration produces the vibration we are studying in this experiment. All periodic motions have certain things in common: 0 They repeat the same path over and over. 0 They take the same amount of time for each repetition. 0 They result from objects seeking to maintain the lowest energy potential. Differences in periodic motion include: o Amplitude - the amount of energy in the vibration. 0 Period - the amount of time it takes for one vibration. 0 Frequency - the number of vibrations per second. How do we describe the motion we see? Is there a way to determine the period of a mass on a spring? What affects the energy of a spring? Materials a medium stretchy spring (not a slinky, that's too stretchy), 50g, 100g, and 200g weights, a stopwatch, a meterstick Procedure 1. Attach the spring at least two meters from the ground. (On a wall is ne, though you'll gain a bit of friction, make sure it won't ha rm the wall.) Place the 50g mass on the spring and adjust the spring by gathering coils until the bottom of the spring with the mass on it is at least 1 meter from the ground. 2. Attach each of the masses, one at a time. Pull the mass down 10 cm and release it. (You may want to have the meterstick set up behind the spring so this is visible to you.) Count the number of oscillations in 20 seconds and record the number. 3. Repeat step 2 with displacements of 20 cm and 30 cm and record the results. Observation and Analysis Oscillations in 20 seconds. 10 cm 20 cm 30 cm 50 g 100 g 200 g Based on your observations, calculate the number of oscillations for one minute