Kaunsa Zyada Khatarnaak? 💥
Ek sawaal socho: aapki taraf ek tennis ball 10 km/h se aa rahi hai, ya ek truck 10 km/h se - kis se aap zyada darenge? Truck se, obviously! Dono ki speed same hai, lekin truck ka mass bahut zyada hai.
Ab doosra sawaal: wahi tennis ball 10 km/h se, ya 200 km/h se (tez serve) - kaunsi zyada khatarnaak? Tez waali! Ab mass same hai, lekin speed alag.
Matlab kisi chalti cheez ka "khatra" ya "dhakka dene ki kshamta" do cheezon par depend karta hai - mass aur velocity. Inhe milakar physics ek quantity banati hai - Momentum (sanvég).
🎳 Momentum Ki Definition
📐 Momentum (p) = mass (m) × velocity (v)
p = m × v
SI unit: kg·m/s (kilogram metre per second). Ye ek vector hai -
iski direction wahi hoti hai jo velocity ki.
Momentum batata hai ki kisi chalti cheez mein "kitni motion" hai. Zyada momentum = usse rokna zyada mushkil, aur wo takkar par zyada nuksaan karti hai.
📌 Do tareeke se momentum badhta hai:
▸ Mass badhaao (bhaari cheez)
▸ Velocity badhaao (tez cheez)
Isi liye ek dheemi truck aur ek tez bike - dono ka momentum bahut ho sakta hai!
🧮 Solved Examples
✔ Example 1 - Simple momentum:
Ek 5 kg ki gend 4 m/s se chal rahi hai. Momentum nikalo.
p = m × v = 5 × 4 = 20 kg·m/s
✔ Example 2 - Truck vs Car (same speed):
Ek 1000 kg ki car aur ek 5000 kg ka truck, dono 10 m/s se chal rahe hain. Momentum compare karo.
Car: p = 1000 × 10 = 10,000 kg·m/s
Truck: p = 5000 × 10 = 50,000 kg·m/s
Truck ka momentum 5 guna zyada - isi liye use rokna 5 guna mushkil!
✔ Example 3 - Mass nikalna:
Ek object ka momentum 60 kg·m/s hai aur wo 12 m/s se chal raha hai. Mass?
p = mv → 60 = m × 12 → m = 60 ÷ 12 = 5 kg
✔ Example 4 - Velocity nikalna:
Ek 2 kg ki cheez ka momentum 30 kg·m/s hai. Velocity?
v = p ÷ m = 30 ÷ 2 = 15 m/s
✔ Example 5 - Units badalna:
Ek 1200 kg ki car 72 km/h se chal rahi hai. Momentum?
Pehle v ko m/s mein: 72 × 5/18 = 20 m/s
p = 1200 × 20 = 24,000 kg·m/s
🥊 Force Aur Momentum Ka Connection
Momentum ka sabse bada istemaal ye hai ki wo force se juda hai. Newton ke doosre niyam (agla lesson) ke anusaar:
📌 Force = momentum ke badalne ki dar (rate of change of momentum)
Yaani agar momentum tezi se badle (kam time mein), toh zyada force lagti hai.
Isi se ek bahut important idea nikalta hai: agar momentum ka change zyada time mein ho, toh force kam lagti hai (aur nuksaan kam hota hai). Isi principle par kai suraksha cheezein bani hain:
Ek cricketer tez aati gend ko catch karte waqt apne haath peeche kheench leta hai - isse gend ka momentum zyada time mein zero hota hai, toh haath par force kam lagti hai aur chot nahi lagti! Agar haath ek jagah rakhkar catch karo toh gend zor se lagti hai.
Gaadiyon mein aage ka hissa jaan-boojhkar pichak (crumple) jaane wala banaya jaata hai, aur airbag hoti hai. Ye takkar ke waqt momentum change ka time badha dete hain, jisse passenger par force kam lagti hai aur jaan bachti hai. Physics zindagi bachati hai!
High jump ya gymnastics mein athlete naram gaddi par girte hain, pakki zameen par nahi. Gaddi girne ka time badha deti hai, force kam ho jaati hai, aur chot nahi lagti - wahi momentum wala principle!
Do carts ka mass aur velocity set karo aur dekho collision ke pehle aur baad momentum barabar rehta hai!
Open Sim →✏️ Khud Try Karo (Practice)
Q. Solve karo (answers neeche):
- Ek 3 kg ki cheez 6 m/s se chal rahi hai. Momentum?
- Ek object ka momentum 100 kg·m/s hai, mass 20 kg. Velocity?
- Ek 800 kg ki car 90 km/h se chal rahi hai. Momentum?
Answers: 1) 3 × 6 = 18 kg·m/s 2) 100 ÷ 20 = 5 m/s 3) v = 90×5/18 = 25 m/s, p = 800×25 = 20,000 kg·m/s
🧠 Chalo Test Karein! (Quick Quiz)
Apne aap ko check karo 👇
📌 Aage Kya? (Coming Next)
Ab hum Newton ka doosra niyam padhenge - jo force, mass aur acceleration ko ek famous formula F = ma mein jodta hai!