Can Waves Really Transmit Angular Momentum?

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Waves can indeed transmit angular momentum, contrary to some beliefs. Electromagnetic waves, particularly circularly polarized light, can carry both orbital and spin angular momentum, causing objects like plates to twist when exposed to them. Similar principles apply to mechanical waves; for instance, sending circular waves down a rope connected to a rotating disc can impart angular momentum to the disc, causing it to spin. These experiments demonstrate the ability of waves to transfer angular momentum effectively. Understanding this phenomenon has implications in various fields of physics and engineering.
Himal kharel
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why can't a wave transmit angular momentum?
 
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They can and do. Electromagnetic waves can carry both orbital and spin angular momentum. If you shine a beam of circularly polarized light on a plate, the plate will twist slightly. This has been http://prola.aps.org/abstract/PR/v50/i2/p115_1" .

You could do a similar experiment with waves on a string. Connect a rope to one edge of a disc mounted so that it is free to rotate about its axis. Hold the other end and send circular waves down the rope and you will be able to get the disc spinning. The angular momentum in the wave is imparted to the disc.
 
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Thread 'Mousetrap Car Energy efficiency'

For simple comparison, I think the same thought process can be followed as a block slides down a hill, - for block down hill, simple starting PE of mgh to final max KE 0.5mv^2 - comparing PE1 to max KE2 would result in finding the work friction did through the process. efficiency is just 100*KE2/PE1. If a mousetrap car travels along a flat surface, a starting PE of 0.5 k th^2 can be measured and maximum velocity of the car can also be measured. If energy efficiency is defined by...
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