跳到主要內容

Pendulum and damping

Plumb bob is actually a type of pendulum.

Movement is determined by Simple harmonic motion

period of the pendulum was approximately 

2*Pi*sqrt(l/g)

Damping and critically damping 


Water vs air:

40 sec vs 60 sec 

Dry and viscous damping

Flapping of bird pendulum 

By air



Diameter of string 

Helm string麻繩 vs nylon line: 40 sec vs 70 ~80 sec

Eddy current and Magnetic damping

Reinventing ideas 

Initial experiment with an existing plumb bob and two simple magnets is not too successful, needs more fine tuning. Otherwise you are making a chaotic pendulum instead. TBD.


Another YouTube 

Xmdemo by varying the magnet to damper distance

Magnetic braking(eddy current) with copper plate:



ME230

Reverse "Laser" plumb bob, laser firing upwards


Laser firing downwards：



Shinwa ， 易之力 EZX-038

Sikana , using a wooden block with hole

Plumb bob should be as close to wall as possible, almost touching.

Stackexchange

Isaac

Plumb bobs , storable 

Constructor org

Temple builder

Smartbob

Curso albanilera

Primar pilar

Magnetic damping line for ship patent 

How to thread 

Tuned mass damper in buildings and suspension bridges


In Tamiya 4WD 

1.2mm  masonry cord, polyethylene meister brick line

留言

張貼留言

這個網誌中的熱門文章

ES8311 and ES8388 codec IC

ES8388 audio codec module is one of the audio codec modules available that is supported by ESP32 and official ESP-ADF releases. The ES8388 module lets you have: Stereo microphone and line input Stereo headphone and line out Up to 96 kHz 24 bpp high quality audio This module is compatible with all MCUs that have I2C and I2S ports (like ESP32, ESP8266, STM32, i.MX6, Raspberry Pi, etc) ES8311 Maxgerhardt github PCBartist twblogs ESP32-A1S  (limited stock)Audio codec AC101 or ES8388 built-in. NB the pinouts and firmware are different! Arduino - ESP31-A1S instructable Phil Schatzmann and his github   Simple A2DP thaaraak github on ESP32-A1S github of Yveaux and  Marcel-licence ESP ADF   example:  Logitech PiCorePlayer squeeze lite squeezebox forum   ESP32-Audio-kit  (from AI thinker) based on ESP32-A1S, is simple and small. But upgrade-ability seems limited  Alex John Talbert mixer equalizer: can this be used as simple equalizer? how about proces...
張貼留言
閱讀完整內容

sharpstar 150mm f/2.8 hyperbolic astrograph

to be launched in summer, 2019. spot diagram is now available, and connections diagram to camera is shown . list price RMB 13,000 ( USD 1900 approx) comparing this with Takahashi epsilon-180ED: spot diagram: connections: the focuser is 2.5 inch, and threads are M48 x 0.75mm   cloudynights first impression threads   some nice photo review from skypoint   Astrofotoblog review  c
2 則留言
閱讀完整內容

越南香草

Ngo ~ "N-gaw" Mui ~ "Moo-ee" Ngo ~ "N-gaw" Mui ~ "Moo-ee" Ngo ~ "N-gaw" Mui ~ "Moo-ee" Ngo (N-gaw) ,  Mui  (Moo-ee )  Cilantro Coriandrum sativum, chinese parsley  Ngo Gai (N-gaw guy), Mui Tau (Moo-ee Tao), Ngo Tau (N-gaw Tao)   Mexican Coriander,  Sawtooth Coriander, Cilantro Eryngium foetidum 　　 娥女帝(拼音), 刺芹 　　特徵：娥女帝是短株形的植物，氣味清淡，葉邊呈鋸齒形，十分容易辨認。來源地：越南。 功效：和白夏差不多，娥女帝亦有祛濕、解毒及驅風的療效。建議食法： Pho,  (Bánh Xeò) 越南煎餅, 炒菜,湯,咖哩 Ngo Gai ~ "N-gaw guy" Mui Tau ~ "Moo-ee Tao" Ngo Tau ~ "N-gaw Tao" - See more at: http://vietworldkitchen.typepad.com/blog/vietnamese-herb-primer.html#sthash.I9rzkzwI.dpuf Rau Ram (Rau Rahm) Vietnam Coriander, Laksa Leaf, "Vietnamese mint(actually not a mint)". Polygonum leaf Polygonum odoratum Peppery, quite spicy. In salad, soup Hung (Hoong), , Hung Lang (Hoong Lang) Spearmint.  Vietnamese coriander Hung Lui (Hoong Lou-ee), Hung ...
張貼留言
閱讀完整內容