gharshan

dharati par rakhe ek block ke liye free-baudi aarekh

gharshan (Friction) ek bal hai jo do talon ke beech saapekshik sparshi gati ka virodh karta hai. yeh gati ka virodh karta hai. gharshan bal ka maan donon talon ke beech abhilanb bal par nirbhar karta hai.

gharshan ke do prakaar hain: sthaitik aur gatij. sthaitik gharshan do pindon ke sampark-prushth ki samaantar disha mein lagta hai, lekin gatij gharshan gati ki disha par nirbhar nahi karta.

anukram

gharshan ka kaaran

saamaanyat: koi satah poornataya chikni naheen hoti, apitu usamein atyalp parimaan ke uthaav aur gaddhe hote hain. inko achhe sookshmadarshi dvaara hi dekha ja sakta hai. at: jab aisi do satahein ek doosare ko sparsh karti hain, to ek satah ke uthaav doosari satah ke gaddhon mein fains jaate hain. is avastha mein ek satah ko doosari satah par khiskaane ke liye bal lagaane par satah ki banaavat mein vikrut utpann ho jaati hai. isi ke anuroop padaartho ki pratyaasthata ke kaaran prayukt bal ki viruddh disha mein pratibl kaarya karta hai, jise gharshanabal kehte hain.

gharshan ke upayog

hamaare dainik jeevan mein gharshan ka bahut mahatvapoorn sthaan hai. pruthvi ki satah par chalanevaale pratyek vaahan ki gati satah tatha vaahan ke aadhaar ke beech gharshanabal dvaara hi sambhav hai. at: gharshan gati baadhak tatha saadhak donon hi hai. dhaaruk aur snehakon ke vyavahaar mein bhi gharshan ka pramukh sthaan hai.

gharshan ka parimaan

baaloo ki dheri svat: hi shanku ka aakaar grahan kar leti hai. is shanku ka jhukaav kon aantarik gharshan ke baraabar hota hai.

Sand adopts a cone shape with the inclination angle of the internal friction. kisi thos padaarthapind ko thos satah par visthaapit karne ke liye sparsh satah ke samaantar bal prayukt karna hota hai. yadi prayukt bal ek nishchit parimaan (charam gharshanabal) se kam hua, to padaarthapind visthaapit naheen hota aur yadi adhik hua to nishchit veg se visthaapit hota hai. aisa sparsh karanevaali satahon ke beech gharshan ke kaaran hota hai, jisse taatparya yeh hai ki thos padaarthapind par sparsh satah ke samaantar prayukt bal ki viruddh disha mein ek bal kaarya karta hai, jise gharshan bal kehte hain. gharshan bal ka kaaran satahon ka khuraduraapan hota hai.

visthaapan se poorv (jab pind sthir hon) gharshanabal prayukt bal ke baraabar hota hai, jise sthaitik gharshan kehte hai. visthaapan ke liye prayukt bal kam se kam itne parimaan ka hona chaahiye ki vikruti charam pratyaasthata se adhik ho. visthaapan ke liye aavashyak is nyoonatam bal ke parimaan ko charam gharshanabal kehte hain.

charam gharshanabal (Fa) tatha dono satahon ke beech abhilanbi daab (P) mein nimnalikhi sambandh hota hai :

Fa = b1 P

jabki (b1) sthaitik dharshanasthiraank kahalaata hai. iska maan padaarthapind ko satah par rakhakar satah par rakhakar satah ka nyoonatam jhukaav kon (q), jispar padaarthapind fislan praarambh kare, gyaat karke maaloom kar sakte hain. is kon ko gharshanakon kehte hain. gharshanakon ki sparshajya hi parimaan mein sthaitik gharshanasthiraank ke baraabar hoti hai, arthaat‌

b1 = tan q

gati ke samay bhi padaarthapind par gharshanabal kaarya karta hai. iska parimaan mukhyataya visthaapan ke prakaar par nirbhar karta hai. ek thos padaarthapind ko thos satah par khiskaakar ya ludhkaakar hi visthaapit kar sakte hain; at: inheen do visthaapan prakaaron ke anusaar nimnaankit do prakaar ke gateeya gharshan hote hain.

1 - visrpi (sliding) gharshan

2 - lunthan (rolling) gharshan

donon prakaar ki gatiyon ke liye gharshanabal ka parimaan nimnalikhit sootr dvaara vyakt kiya jaata hai :

Fb = bc x P

jabki (Fb) gharshanabal, (P) satah par abhilanbi daab tatha (bc) gatij gharshan sthiraank hai, jiska maan donon satahon par nirbhar karta hai. satahon ki laghu saapeksh gati ke liye kag ka maan gati ke parimaan par nirbhar naheen karta. parantu jab gati ka parimaan kraantik veg (critical velocity) se adhik ho jaata hai, to veg ki vruddhi ke saath saath kag ka maan hota jaata hai. kag ka maan lunthan tatha sarpan (rolling and sliding) gatiyon ke liye bhinn bhinn hota hai.

kuchh padaarthon ke gharshan-gunaank

neeche kuchh padaarthon ke gharshan-gunaakon ka sannikt maan diya gaya hai.

iske-ke beech (padaarth) sthaitik gharshan,
sookha aur saaf snehit (Lubricated)
aluminiym ispaat 0.61
taaainba ispaat 0.53
Brass Steel 0.51
Cast iron Copper 1.05
Cast iron Zinc 0.85
Concrete Rubber 1.0 0.30 (wet)
Concrete Wood 0.62[1]
Copper Glass 0.68
Glass Glass 0.94
Metal Wood 0.2–0.6[1] 0.2 (wet)[1]
Polyethene Steel 0.2[2] 0.2[2]
Steel Steel 0.80[2] 0.16[2]
Steel PTFE (Teflon) 0.04[2] 0.04[2]
PTFE (Teflon) PTFE (Teflon) 0.04[2] 0.04[2]
Wood Wood 0.25–0.5[1] 0.2 (wet)[1]

inhein bhi dekhein

  • roling gharshan (Rolling resistance)
  • apagharshak (abrasive))
  • tyre (Tire)
  • karshan (Traction)
  • ghisn (Wear)

sandarbh

baahari kadiyaaain