0:00:06.766,0:00:11.733 Cordless earbuds are convenient. 0:00:12.900,0:00:17.900 When earbuds get caught on something, 0:00:19.133,0:00:24.800 they'll come flying out of your ears, but 0:00:25.966,0:00:32.200 otherwise, they usually stay in your ears well enough. 0:00:32.866,0:00:38.166 Even doing a spin is totally fine 0:00:41.833,0:00:47.466 But if you keep spinning faster and faster... 0:00:50.100,0:00:57.900 Eventually, your centrifugal force [br]should be able to pull out your earbuds. 0:00:59.033,0:01:05.337 So how fast would you have to spin[br]for your earbuds to fall out? 0:01:05.353,0:01:07.623 Centrifugal force is determined by mrω² 0:01:07.623,0:01:13.729 m = mass of an earbud[br]r = radius (earbud's distance from the axis)[br]ω = angular velocity 0:01:13.729,0:01:20.233 First, measure the force required to remove the earbuds. 0:01:20.233,0:01:26.533 I used this spring scale to measure it. 0:01:27.933,0:01:34.433 Make sure that your earbuds'[br]tip covers are on correctly 0:01:34.800,0:01:40.833 Pull straight 0:01:41.700,0:01:49.466 It took 0.73 newtons to remove the earbud.[br](plus or minus 0.007) 0:01:50.033,0:01:56.200 So if we take one 5.4g earbud 0:01:56.200,0:02:02.500 and gradually increase its weight... 0:02:05.266,0:02:12.866 it should separate when it goes above 74g,[br]which is about the weight of a large egg. 0:02:12.866,0:02:19.066 Now, let's make the person wearing these earbuds spin at high speed. 0:02:20.033,0:02:27.100 Keep in mind, the axis of rotation is the[br]point directly between both earbuds. 0:02:28.568,0:02:35.866 I made it a fixed axis so it won't wobble[br]no matter how fast he goes. 0:02:35.866,0:02:44.266 I'm going to gradually increase[br]the rotations per second. 0:02:51.100,0:03:02.866 The earbuds fell out after passing 6.5 rotations per second. 0:03:04.633,0:03:12.800 At the point of exit, the earbuds were being[br]subjected to 13.8 Gs of force. 0:03:14.646,0:03:22.446 Let's put this speed into perspective. 0:03:23.966,0:03:30.500 Looking up the figure skater records for jumps, 0:03:31.800,0:03:40.766 even Yuzuru Hanyu, who is going for the quadruple Axel, [br]is said to have 5.71 revolutions per second. 0:03:40.766,0:03:45.400 So even a Hanyu-level spin,[br]which you're looking at now, 0:03:46.566,0:03:53.100 it's safe to say your earbuds [br]probably won't come out. 0:03:54.600,0:04:00.566 On the other hand, the glasses (20g)... 0:04:01.666,0:04:07.966 started to shift at about 0.6N. 0:04:09.066,0:04:24.700 Earphones fall out > Hanyu spin > Glasses slip off 0:04:24.700,0:04:30.666 So, since spinning almost definitely won't[br]make your earbuds come out, 0:04:32.133,0:04:38.233 all you have to worry about is them[br]getting caught on something.