Driven Oscillation

A demonstration of the phase condition for resonance. Think back to pumping a swing when you were a kid. You had to push back and forth at a specific frequency - the natural frequency of the pendulum (you!). Perhaps you also remember pushing hardest just before reaching the top. That is the pi/2 phase lag. This was my very first weird teaching video.
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Welcome to Physierge - your concierge for learning physics!
I'm a professor at Rice University where I have taught introductory physics for the past 10 years. My channel ( / ricephysics102 ) features short lectures and worked problems that will complement your calculus-based introductory physics courses.
If you are looking for a complete online course with full lectures, demonstrations, homework, exams, and an active discussion forum, consider one of my online classes at edX:
PHYS102x Electricity & Magnetism, part 1
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PHYS102x Electricity & Magnetism, part 2
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PHYS201x Waves & Optics
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For non-calculus based introductory physics, we have made AP Physics 1, also at edX:
AP Physics 1
www.edx.org/co....
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The edX classes were produced by Rice Online (online.rice.edu/) which offers great classes in many areas.
We also work with OpenStax College (openstax.org), who has several free textbooks online, including non-calculus and calculus-based physics.