COSAM » Departments » Physics » Introductory Courses » Demonstrations » Waves and Resonance » Oscillations

OSCILLATIONS

3A10.10 SIMPLE PENDULUM
3A15.10 PHYSICAL PENDULUM (ROD)
3A15.25 PHYSICAL PENDULUM (RING)
3A20.10 MASS ON SPRING
3A60.10 TACOMA NARROWS BRIDGE COLLAPSE TAPE
3A60.40 DRIVEN MECHANICAL RESONANCE
3A70.10 WILBERFORCE PENDULUM
3A70.20 COUPLED PENDULA

 3A10.10 Simple Pendulum Suspend a simple pendulum from a rod. Use as visual aid when talking about pendulum. You can also determine period and show related to length. Setup Requirements: Assembled as needed. Stopwatch and meter stick optional. Several types of balls, weights and string available.   Equations: Period proportional to square root of length.   Safety Issues: None

 3A15.10 Physical Pendulum (Rods) Distributed mass pendulum instead of mass concentrated on end. Setup Requirements: Some assembly required. Meter stick, ring and baseball bat versions also available.    Equations: Period depends on moment of inertia about pivot point. Period = 2 pi x square root of I/mgh.   Safety Issues: None

 3A15.25 Physical Pendulum (Ring) A ring oscillates on a rod. A v shaped piece of metal is placed over top of the rod to serve as a knife edge. Ring has the same period as simple pendulum with length equal to diameter of ring if thickness of ring is ignored.   Setup Requirements: Assembled as needed. Large ring period is 1.09 sec. Equations:  Period ~ 2 x pi x (D/g)1/2 Safety Issues:  None

 3A20.10 Mass on a spring A mass oscillates slowly on a large spring. Use as visual aid or time to show period depends on mass. Setup Requirements: Assembled as needed. Stopwatch optional .   Equations: Period proportional to squareroot of m/k.   Safety Issues: None

 3A60.10 Tacoma Narrows Bridge Film Show a film of the oscillations of the bridge due to "resonance" and the subsequent collapse. Located in Miller Collection Tapes(yellow cover) Unit II.  Setup Requirements: Requires television & VCR on cart or VCR in classroom.   Equations: For information about physics involved see  http://www.umsl.edu/%7efeldmanb/pdfs/tacoma_bridge.pdf and  http://www.aapt.org/Store/upload/tacoma_narrows2.pdf   Safety Issues: None

 3A60.40 Driven Mechanical Resonance Signal generator connected to spring can be varied in frequency to show resonance in driven system. The signal generator could represent an earthquake and the spring a building.   Setup Requirements: Assembled as needed   Equations: If driving frequency(w) is near resonant frequency, amplitude builds up. Maximum amplitude = F(0)/(bw) where b is damping coefficient.   Safety Issues: Vibration amplitude so high spring comes loose.

 3A70.10 Wilberforce Pendulum Exhibits pendulum type motion, spring type motion, and rotational motion. Energy is passed back and forth between translational and rotational motion. Setup Requirements: Assembled as needed   Equations: Conservation of Mechanical Energy    Safety Issues: None

 3A70.20 Coupled Pendula Hang multiple pendula from a rod. Start one moving. Another pendulum with same length will start moving. A pendulum with say twice the length will not move much. Setup Requirements: Assembled as needed. May differ from photograph.   Equations: None   Safety Issues: None

Last Updated: 07/12/2016