{"id":407,"date":"2021-01-18T00:54:04","date_gmt":"2021-01-18T05:54:04","guid":{"rendered":"http:\/\/research.phys.cmu.edu\/physdemos\/?page_id=407"},"modified":"2021-01-20T20:50:45","modified_gmt":"2021-01-21T01:50:45","slug":"balls-in-rotating-cups","status":"publish","type":"page","link":"https:\/\/research.phys.cmu.edu\/physdemos\/home\/balls-in-rotating-cups\/","title":{"rendered":"Balls in Rotating Cups"},"content":{"rendered":"<div class=\"et_d4_element et_pb_section et_pb_section_0  et_pb_css_mix_blend_mode et_section_regular et_block_section\" >\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<div class=\"et_d4_element et_pb_row et_pb_row_0  et_pb_css_mix_blend_mode et_block_row\">\n\t\t\t\t<div class=\"et_d4_element et_pb_column_1_3 et_pb_column et_pb_column_0  et_pb_css_mix_blend_mode et_block_column\">\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<div class=\"et_pb_module et_d4_element et_pb_accordion et_pb_accordion_0\">\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<div class=\"et_pb_toggle et_pb_module et_d4_element et_pb_accordion_item et_pb_accordion_item_0  et_pb_toggle_open\">\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<h3 class=\"et_pb_toggle_title\">TEST KEEP CLOSED<\/h3>\n\t\t\t\t<div class=\"et_pb_toggle_content clearfix\"><\/div>\n\t\t\t<\/div><div class=\"et_pb_toggle et_pb_module et_d4_element et_pb_accordion_item et_pb_accordion_item_1  et_pb_toggle_close\">\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<h3 class=\"et_pb_toggle_title\">MECHANICS<\/h3>\n\t\t\t\t<div class=\"et_pb_toggle_content clearfix\"><p><strong>Mechanics<\/strong><\/p>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/the-monkey-and-the-hunter\/\">The Monkey and The Hunter<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/simultaneously-shoot-and-drop-a-pair-of-spheres\/\">Simultaneously Shoot and Drop Pair of Spheres<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/projectile-launched-vertically-from-a-moving-cart\/\">Projectile Launched Vertically from a Moving Cart<\/a><\/li>\n<\/ul>\n<p><strong>Newt's Laws of Motion<\/strong><\/p>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/newtons-1st-law-on-an-air-track\/\">Newton's First Law<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/newtons-2nd-law-on-an-air-track\/\">Newton's Second Law<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/newtons-3rd-law-water-rocket\/\">Newton's Third Law<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/blackboard-mechanics-kit\/\">Blackboard Mechanics Kit<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/cork-bob-accelerometer\/\">Cork Bob Accelerometer<\/a><\/li>\n<\/ul>\n<p><strong>Work and Energy<\/strong><\/p>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/the-bowling-ball-pendulum\/\">Bowling Ball Pendulum<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/blocked-pendulum\/\">Blocked Pendulum<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/loop-the-loop\/\">Loop-The-Loop<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/coefficients-of-friction\/\">Coefficients of Friction<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/friction-cart\/\">Friction Cart<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/energy-stored-in-a-spring\/\">Energy Stored in a Spring<\/a><\/li>\n<\/ul>\n<p><strong>Mechanical Equilibrium<\/strong><\/p>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/center-of-gravity\/\">Assorted Center of Gravity Demos<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/catenary-bi-stable-equilibrium\/\">Catenary: Bi-Stable Equilibrium<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/mass-on-spring-hookes-law\/\">Mass on Spring: Hooke's Law<\/a><\/li>\n<\/ul>\n<p><strong>Collisions and Conservation of Momentum<\/strong><\/p>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/explosions\/\">Explosions<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/totally-inelastic-collisions\/\">Totally Inelastic Collisions<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/elastic-collisions\/\">Elastic Collisions<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/newtons-cradle\/\">Newton's Collision Apparatus<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/internal-degrees-of-freedom-during-collisions\/\">Internal Degrees of Freedom<\/a><\/li>\n<\/ul>\n<p><strong>Circular Motion<\/strong><\/p>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/balls-in-rotating-cups\/\">Balls in Rotating Cups<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/loop-the-loop\/\">Loop-the-Loop<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/swinging-water-bucket\/\">Elastic Collisions<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/swinging-water-bucket\/\">Swinging Water Bucket Overhead<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/conical-pendulum\/\">Conical Pendulum<\/a><\/li>\n<\/ul>\n<p><strong>Rigid Body Rotations<\/strong><\/p>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/assortment-of-rolling-things\/\">Assortment of Rolling Things<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/moment-of-inertia-of-a-solid-disk\/\">Moment of Inertia of a Solid Disk<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/a-windlass-with-variable-moment-of-inertia\/\">Windlass with Variable Moment of Inertia<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/demonstrator-on-a-rotating-stool-with-dumbbells\/\">Rotating Stool with Dumbbells<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/demonstrator-on-a-rotating-stool-with-weighted-bicycle-wheel\/\">Rotating Stool with a Bicycle Wheel<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/gyroscopes\/\">Gyroscopes<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/rotating-reference-frame\/\">Rotating Reference Frame<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/parallel-and-non-parallel-angular-velocity-and-momentum\/\">Parallel and Non-Parallel Angular Velocity and Momentum<\/a><\/li>\n<\/ul><\/div>\n\t\t\t<\/div><div class=\"et_pb_toggle et_pb_module et_d4_element et_pb_accordion_item et_pb_accordion_item_2  et_pb_toggle_close\">\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<h3 class=\"et_pb_toggle_title\">OSCILLATIONS AND WAVES<\/h3>\n\t\t\t\t<div class=\"et_pb_toggle_content clearfix\"><p><strong>Periodic Motion<\/strong><\/p>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/assorted-oscillating-things\/\">Oscillating Things<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/simple-mass-spring-system\/\">Simple Mass-Spring System<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/damped-harmonic-motion\/\">Damped Harmonic Motion<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/simple-pendulum\/\">Simple Pendulum<\/a><\/li>\n<\/ul>\n<p><strong>Driven Oscillations and Resonance Phenomena<\/strong><\/p>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/driven-damped-harmonic-motion\/\">Driven, Damped Harmonic Oscillator<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/resonance-with-a-speaker-and-adjustable-pipe\/\">Resonance with a Speaker and Adjustable Pipe<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/driven-pendulum-parametric-resonance\/\">Driven Pendulum<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/modes-of-vibration\/\">Modes of Vibration<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/pair-of-compound-pendulums-chaos\/\">Compound Pendulum<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/chaotic-oscillations-magnetic-pendulum\/\">Chaotic Oscillations<\/a><\/li>\n<\/ul>\n<p><strong>Propagation of Mechanical Waves<\/strong><\/p>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/transverse-pulses-on-a-long-rubber-tube\/\">Transverse Pulses<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/longitudinal-pulses-on-a-slinky\/\">Longitudinal Pulses<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/reflection-transmission-at-a-boundary\/\">Reflection or Transmission at a Boundary<\/a><\/li>\n<\/ul>\n<p><strong>Superposition of Waves<\/strong><\/p>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/transverse-standing-waves-on-a-long-coil-spring\/\">Transverse Standing Waves<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/torsional-standing-waves\/\">Torsional Standing Waves<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/longitudinal-standing-waves\/\">Longitudinal Standing Waves<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/fourier-synthesizer\/\">Fourier Synthesizer<\/a><\/li>\n<\/ul>\n<p><strong>Normal Modes of Vibration<\/strong><\/p>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/normal-modes-in-one-dimension\/\">One dimension<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/normal-modes-of-a-plucked-string\/\">A Plucked String<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/normal-modes-of-a-driven-vibrating-string\/\">A Driven Vibrating String<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/weakly-coupled-pendulums\/\">Weakly Coupled Pendulums<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/compound-pendulum\/\">Compound Pendulum<\/a><\/li>\n<\/ul>\n<p><strong>Acoustic Phenomena<\/strong><\/p>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/doppler-effect\/\">Doppler Effect<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/beat-frequencies\/\">Beat Frequencies<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/interference-of-sound-waves\/\">Interference of Sound Waves<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/sympathetic-vibrations-in-tuning-bars\/\">Sympathetic Vibrations in Tuning Bars<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/speed-of-sound-in-air-and-in-helium\/\">Speed of Sound in Air and Helium<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/speed-of-sound-in-a-metal-bar\/\">Speed of Sound in a Metal<\/a><\/li>\n<\/ul><\/div>\n\t\t\t<\/div><div class=\"et_pb_toggle et_pb_module et_d4_element et_pb_accordion_item et_pb_accordion_item_3  et_pb_toggle_close\">\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<h3 class=\"et_pb_toggle_title\">OPTICS<\/h3>\n\t\t\t\t<div class=\"et_pb_toggle_content clearfix\"><p><strong>Geometrical Optics<\/strong><\/p>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/blackboard-optics-kit-reflection-refraction\/\">Blackboard Optics Kit<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/dispersion-in-a-prism\/\">Dispersion in a Prism<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/total-internal-reflection\/\">Total Internal Reflection<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/fiber-optic-cables\/\">Fiber Optic Cables<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/speed-of-light-from-electrical-pulses\/\">Speed of Light<\/a><\/li>\n<\/ul>\n<p><strong>Interference and Diffraction<\/strong><\/p>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/single-slit-diffraction\/\">Single Slit<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/double-slit-diffraction\/\">Double Slit<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/multiple-slits-and-gratings\/\">Multiple Slits and Gratings<\/a><\/li>\n<li>Thin Film Interference:<\/li>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/wedged-optical-flats\/\">Wedged Optical Flats<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/thin-film-interference-soap-bubbles\/\">Soap Bubbles<\/a><\/li>\n<\/ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/thin-film-interference-newtons-rings\/\">Newton's Rings<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/circular-obstacle-diffraction-poissons-spot\/\">Poisson's Spot<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/michelson-interferometer\/\">Michelson Interferometer<\/a><\/li>\n<\/ul>\n<p><strong>Polarization<\/strong><\/p>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/polarization-by-transmission\/\">By Transmission<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/polarization-by-reflection\/\">By Reflection<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/polarization-of-scattered-light\/\">Scattered Light<\/a><\/li>\n<\/ul><\/div>\n\t\t\t<\/div><div class=\"et_pb_toggle et_pb_module et_d4_element et_pb_accordion_item et_pb_accordion_item_4  et_pb_toggle_close\">\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<h3 class=\"et_pb_toggle_title\">THERMAL PROPERTIES OF MATTER<\/h3>\n\t\t\t\t<div class=\"et_pb_toggle_content clearfix\"><p><strong>Thermal Expansion<\/strong><\/p>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/thermal-expansion-of-a-brass-tube\/\">Expansion of Brass Tube<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/differential-expansion-bi-metallic-strip-thermostat\/\">Bi-Metallic Thermostat<\/a><\/li>\n<\/ul>\n<p><strong>Thermal Conductivity<\/strong><\/p>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/conduction-of-heat-through-dissimilar-metals\/\">Dissimilar Metals<\/a><\/li>\n<\/ul><\/div>\n\t\t\t<\/div><div class=\"et_pb_toggle et_pb_module et_d4_element et_pb_accordion_item et_pb_accordion_item_5  et_pb_toggle_close\">\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<h3 class=\"et_pb_toggle_title\">THERMODYNAMICS<\/h3>\n\t\t\t\t<div class=\"et_pb_toggle_content clearfix\"><h4>Pressure-Volume-Temperature Relationships<\/h4>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/adiabatic-gas-law\/\">Adiabatic Gas Law<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/pressure-differences\/\">Pressure Differences<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/balloon-in-evacuated-bell-jar-model-lung\/\">Model Lung<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/boyles-law-apparatus\/\">Boyle's Law<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/volume-and-temperature-at-constant-pressure\/\">V-T Relationship at Constant Pressure<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/p-v-t-surface-for-water\/\">P-V-T Surface for Water<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/diffusion-through-an-aperature\/\">Diffusion Through an Aperture<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/p-t-relation-at-constant-volume\/\">P-T Relation at Constant Volume<\/a><\/li>\n<\/ul>\n<h4>Many Particle Systems<\/h4>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/equipartition-of-energy-in-a-mixed-gas\/\">Equipartition of Energy in a Mixed Gas<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/kinetic-theory-and-diffusion-balls-in-an-aspirator-jar\/\">Kinetic Theory &amp; Diffusion<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/brownian-motion-simulation\/\">Brownian Motion Simulation<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/solid-liquid-gas-transitions\/\">Solid-Liquid-Gas Transitions<\/a><\/li>\n<li>Heat Engines:<\/li>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/heat-engine-drinking-bird\/\">Drinking Bird<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/stirling-cycle-heat-engine\/\">Stirling Cycle<\/a><\/li>\n<\/ul>\n<\/ul><\/div>\n\t\t\t<\/div><div class=\"et_pb_toggle et_pb_module et_d4_element et_pb_accordion_item et_pb_accordion_item_6  et_pb_toggle_close\">\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<h3 class=\"et_pb_toggle_title\">ELECTRICITY &amp; MAGNETISM <\/h3>\n\t\t\t\t<div class=\"et_pb_toggle_content clearfix\"><h4>Electric Charge and Field<\/h4>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/positive-and-negative-charge-by-friction\/\">Positive and Negative Charge by Friction<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/induced-surface-charge-on-conductors\/\">Induced Surface Charge on Conductors<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/coulombs-law-apparatus\/\">Coulomb's Law<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/distribution-of-surface-charge-on-conductors\/\">Distribution of Surface Charge on Conductors<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/capacitors-and-energy-storage\/\">Capacitors and Energy Storage<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/capacitor-voltage-vs-plate-separation-and-dielectric-constant\/\">Capacitance vs. Plate Separation<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/electric-sparks-and-ionization-effects\/\">Van de Graaff<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/jacobs-ladder\/\">Jacob's Ladder<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/electric-field-lines\/\">Electric Field Lines<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/force-on-a-moving-charge-in-an-electric-field\/\">Force on a Moving Charge in an Electric Field<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/flux-surface-and-volume\/\">Flux Surface and Volume<\/a><\/li>\n<\/ul>\n<h4>Current and Resistance<\/h4>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/resistors-in-series-and-parallel\/\">Resistors in Series and Parallel<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/internal-resistance-of-a-battery\/\">Internal Resistance of a Battery<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/ohmic-and-non-ohmic-devices\/\">Ohmic and Non-Ohmic Devices<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/drift-velocity\/\">Drift Velocity Demonstrator<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/the-wire-fryer-dc-version\/\">Wire Fryer (DC version)<\/a><\/li>\n<\/ul>\n<h4>Magnetic Field and Forces on Currents<\/h4>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/magnetic-domain-model\/\">Magnetic Domain Model<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/magnetic-field-of-a-permanent-magnet\/\">Magnetic Field of Permanent Magnets<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/earths-magnetic-field-dip-needle\/\">Earth's Magnetic Field: Dip Needle<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/magnetic-field-of-a-current-carrying-wire\/\">Magnetic Field of Currents<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/magnetic-field-inside-a-solenoid\/\">Magnetic Field of a Solenoid<\/a><\/li>\n<li>Magnetic Force on an Electron Beam:<\/li>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/magnetic-force-on-an-electron-beam-e-m-experiment\/\">e\/m Experiment<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/magnetic-force-on-an-electron-beam-circular-orbit\/\">Circular Orbit<\/a><\/li>\n<\/ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/magnetic-force-on-a-current-carrying-wire\/\">Magnetic Force on a Current-Carrying Wire<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/magnetic-torque-on-a-current-loop\/\">Magnetic Torque on a Current Loop<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/force-between-two-current-carrying-wires\/\">Force Between Current-Carrying Wires<\/a><\/li>\n<\/ul>\n<h4>Induced Currents and EMF<\/h4>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/faradays-law-and-lenzs-law\/\">Faraday's Law and Lenz's Law<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/enclosed-fields-and-magnetic-induction\/\">Enclosed Fields and Magnetic Induction<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/current-generators\/\">Current Generators<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/dc-motor\/\">DC Motors<\/a><\/li>\n<li>Eddy Currents:<\/li>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/eddy-current-pendulum\/\">Pendulum<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/eddy-current-pipe\/\">Aluminum Pipe<\/a><\/li>\n<\/ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/jumping-rings\/\">Jumping Rings<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/the-wire-fryer-ac-version\/\">Wire Fryer AC<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/transformers-and-flux-linkage\/\">Transformers and Flux Linkage<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/self-inductance-and-energy-storage\/\">Self-Inductance and Energy Storage<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/displacement-current\/\">Displacement Current<\/a><\/li>\n<\/ul>\n<h4>Time Dependent Currents<\/h4>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/rc-time-constants\/\">RC Time Constants<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/rlc-oscillations-and-energy-dissipation\/\">RLC Oscillations and Energy Dissipation<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/resonance-in-a-driven-rlc-circuit\/\">Resonance in a Driven RLC Circuit<\/a><\/li>\n<\/ul>\n<h4>Superconductivity<\/h4>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/resistivity-vs-temperature-for-a-superconductor\/\">Resistivity vs. Temperature<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/meissner-effect-and-magnetic-levitation\/\">Meissner Effect<\/a><\/li>\n<\/ul>\n<h4>Electromagnetic Waves<\/h4>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/dipole-radiator-short-wave-radio\/\">Dipole Radiator<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/two-source-microwave-interference\/\">Two-Source Microwave Interference<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/standing-microwave-pattern\/\">Standing Microwave Pattern<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/microwave-wave-guides\/\">Microwave Guides<\/a><\/li>\n<\/ul><\/div>\n\t\t\t<\/div><div class=\"et_pb_toggle et_pb_module et_d4_element et_pb_accordion_item et_pb_accordion_item_7  et_pb_toggle_close\">\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<h3 class=\"et_pb_toggle_title\">ATOMIC AND NUCLEAR PROCESSES <\/h3>\n\t\t\t\t<div class=\"et_pb_toggle_content clearfix\"><h4>Quantum Physics<\/h4>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/photoelectric-effect\/\">Photoelectric Effect<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/atomic-and-molecular-spectra-direct-viewing\/\">Atomic and Molecular Spectra<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/electron-diffraction\/\">Electron Diffraction<\/a><\/li>\n<\/ul>\n<h4>Nuclear and Particle Physics<\/h4>\n<ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/background-radiation-cosmic-ray-muons\/\">Background Radiation<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/ceramic-dinnerware-with-uranium-glaze\/\">Ceramic Dinnerware with Uranium Glaze<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/half-life-of-indium-116\/\">Half-Life of Indium 116<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/gamma-ray-spectroscopy\/\">Gamma Ray Spectroscopy<\/a><\/li>\n<\/ul><\/div>\n\t\t\t<\/div><div class=\"et_pb_toggle et_pb_module et_d4_element et_pb_accordion_item et_pb_accordion_item_8  et_pb_toggle_close\">\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<h3 class=\"et_pb_toggle_title\">VISUAL AIDS<\/h3>\n\t\t\t\t<div class=\"et_pb_toggle_content clearfix\"><ul>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/visual-aids-resources\/\">Resources<\/a><\/li>\n<li><a href=\"https:\/\/research.phys.cmu.edu\/physdemos\/home\/visual-aids-resources\/#projector\">Computer &amp; Projector<\/a><\/li>\n<\/ul><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div><div class=\"et_pb_button_module_wrapper et_pb_button_0_wrapper et_pb_button_alignment_center et_pb_module \">\n\t\t\t\t<a class=\"et_pb_button et_d4_element et_pb_button_0 et_pb_bg_layout_light et_block_module\" href=\"https:\/\/research.phys.cmu.edu\/physdemos\/demonstration-request\/\">Request A Demonstration<\/a>\n\t\t\t<\/div>\n\t\t\t<\/div><div class=\"et_d4_element et_pb_column_2_3 et_pb_column et_pb_column_1  et_pb_css_mix_blend_mode et-last-child et_block_column\">\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<div class=\"et_pb_module et_d4_element et_pb_text et_pb_text_0  et_pb_text_align_left et_pb_bg_layout_light\">\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<div class=\"et_pb_text_inner\"><h1>Balls in Rotating Cups <\/h1>\n<p>Two ping pong balls are kept in uniform circular motion in a vertical plane by means of a hand-cranked apparatus shown in the photo above.  The apparatus consists of two cups attached to a long rod which is rotated about an axis perpendicular to the rod.  One of the cups is attached at the end of the rod and the other is attached closer to the axis of rotation.  A ball is placed in each cup, and the apparatus is first rotated at an angular velocity such that both balls stay in their respective cups (centripetal acceleration greater than the acceleration due to gravity).  The angular velocity is gradually reduced and students are asked to predict which of the two balls will fall out first.  Since the centripetal force is proportional to the square of the angular velocity times the radius, the ball in the cup closer to the axis of rotation requires a higher angular velocity in order to remain in the cup. <\/div>\n\t\t\t<\/div><div class=\"et_pb_module et_d4_element et_pb_image et_pb_image_0\">\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<span class=\"et_pb_image_wrap \"><img loading=\"lazy\" decoding=\"async\" width=\"347\" height=\"360\" src=\"http:\/\/research.phys.cmu.edu\/physdemos\/wp-content\/uploads\/sites\/4\/2021\/01\/ballsincups.jpg\" alt=\"Balls in Rotating Cups\" title=\"Balls in Rotating Cups\" srcset=\"https:\/\/research.phys.cmu.edu\/physdemos\/wp-content\/uploads\/sites\/4\/2021\/01\/ballsincups.jpg 347w, https:\/\/research.phys.cmu.edu\/physdemos\/wp-content\/uploads\/sites\/4\/2021\/01\/ballsincups-289x300.jpg 289w\" sizes=\"(max-width: 347px) 100vw, 347px\" class=\"wp-image-107\" \/><\/span>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":4,"featured_media":0,"parent":7,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_et_pb_use_builder":"on","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"class_list":["post-407","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/research.phys.cmu.edu\/physdemos\/wp-json\/wp\/v2\/pages\/407","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/research.phys.cmu.edu\/physdemos\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/research.phys.cmu.edu\/physdemos\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/research.phys.cmu.edu\/physdemos\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/research.phys.cmu.edu\/physdemos\/wp-json\/wp\/v2\/comments?post=407"}],"version-history":[{"count":10,"href":"https:\/\/research.phys.cmu.edu\/physdemos\/wp-json\/wp\/v2\/pages\/407\/revisions"}],"predecessor-version":[{"id":1186,"href":"https:\/\/research.phys.cmu.edu\/physdemos\/wp-json\/wp\/v2\/pages\/407\/revisions\/1186"}],"up":[{"embeddable":true,"href":"https:\/\/research.phys.cmu.edu\/physdemos\/wp-json\/wp\/v2\/pages\/7"}],"wp:attachment":[{"href":"https:\/\/research.phys.cmu.edu\/physdemos\/wp-json\/wp\/v2\/media?parent=407"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}