PhysicsKhaga · Class 6-8
Hawa bhi brake lagati hai!
Ek khula kaagaz aur ek gol-matol kiya hua kaagaz ek saath giraoge, toh pehle zameen pe kaun pahunchega?
Socho pehle… phir dekho jawab
Gola kiya hua kaagaz pehle girta hai. Dono ka wazan same hai, par khula kaagaz zyada hawa ko dhakelta hai, aur hawa usse peeche kheenchti hai. Isse air resistance kehte hain.
Jab bhi koi cheez hawa mein chalti hai, hawa ke chhote-chhote kan uske raaste mein aate hain. Woh cheez ko dheema karte hain. Isko hawa ka virodh ya air resistance kehte hain — yeh ek tarah ka friction hi hai.
Jitni badi surface hawa se takraati hai, utna zyada resistance. Isiliye khula kaagaz lehraata hua dheere girta hai. Cycle pe tez chalo toh chehre pe hawa ka dhakka mehsoos hota hai na? Wahi hai yeh.
Parachute isi idea pe kaam karta hai. Bada sa kapda khulta hai, bahut saari hawa pakadta hai, aur girne ki speed kam ho jaati hai. Isse aadmi ya cheez aaraam se utarti hai.
Ghar pe try karo
Do same size ke kaagaz lo. Ek ko khula rakho, doosre ko gola banao. Ek hi unchai se saath chhodo. Phir ek chhote rumaal ke chaaron kono pe dhaaga baandh ke, neeche ek rubber ya chhoti pencil latkao — mini parachute! Dekho kitna dheere utarta hai.
Wow!
Agar hawa na hoti, toh ek pankh aur ek hathoda ek hi speed se girte — chaand pe astronaut ne yeh sach mein kar ke dikhaya tha!
3 sawaal
- Khula kaagaz, gola kiye kaagaz se dheere kyon girta hai?
Jawab dekho
Us pe zyada air resistance lagta hai. Badi surface zyada hawa se takraati hai, isliye zyada resistance lagta hai.
- Parachute ka bada kapda kya karta hai?
Jawab dekho
Hawa pakad ke girne ki speed kam karta hai. Badi surface = zyada air resistance = dheemi landing.
- Air resistance kis cheez ka ek roop hai?
Jawab dekho
Friction. Hawa ke kan chalti cheez ko ragad ke rokte hain — yeh friction ka hi ek type hai.
NCERT se jodo: NCERT Class 8 Science — force aur friction