PhysicsHiranyagarbha · Class 11-12
Pascal ka niyam: chhota zor, bada kaam — hydraulic lift aur gauge pressure
Kabhi socha hai? Garage mein ek mechanic paanv se chhota sa pedal dabata hai aur poori car upar uth jaati hai. Kya yeh jaadu hai, ya energy muft mein mil gayi?
Socho pehle… phir dekho jawab
Na jaadu, na muft energy. Band liquid par lagaya gaya dabaav har jagah bina ghate pahunchta hai (Pascal ka niyam). Chhote piston par chhota bal, bade piston par utna hi dabaav — par bada area, isliye bada bal. Kaam (work) barabar rehta hai: bada piston kam doori chalta hai.
Hydrostatics: kisi gehrai h par absolute pressure P = P₀ + ρgh (P₀ = satah par hawa ka dabaav). Gauge pressure = P − P₀ = ρgh — tyre gauge yahi naapta hai. Hydrostatic paradox: alag shape ke bartanon mein ek hi gehrai par tali ka dabaav barabar, chahe paani ki maatra alag ho.
Pascal ka niyam: band, asampeedya (incompressible) liquid par lagaya dabaav har disha aur har hisse tak bina ghate pahunchta hai. Hydraulic lift: F₁/A₁ = F₂/A₂, isliye F₂ = F₁ × (A₂/A₁). A₂ = 50 A₁ toh bal 50 guna. Volume barabar khisakta hai: A₁d₁ = A₂d₂, isliye F₁d₁ = F₂d₂ — energy conservation bana rehta hai.
Kadi: pedal dabaya, phir tel mein dabaav bana, phir woh har pahiye ke piston tak pahuncha, isliye ek paanv chaaron pahiyon par brake lagata hai — yahi hydraulic brake hai. Hawa ka bulbula ghus jaaye toh woh dab jaata hai aur brake 'spongy' ho jaata hai; isliye brake ka tel bina hawa ka rakhte hain.
Trade-off: bal mein faayda, doori mein keemat. Engineering mein hamesha yahi len-den hai — kuch muft nahi milta.
Humne kya kiya :- P = P₀ + ρgh, gauge pressure aur Pascal ke niyam se hydraulic lift aur brake ka hisaab lagaya.
Isse kya hua :- Samjhe ki chhote bal se bada bal milta hai par doori ki keemat par, aur gehrai ke saath dabaav seedha badhta hai.
Ghar pe try karo
Do alag size ki plastic syringe (bina sui) lo, ek patli pipe se jodo aur paani bharo (hawa ke bulbule nikaalo). Patli syringe dabao aur moti ka piston kitna chala, naapo; phir ulta karo. A₁d₁ = A₂d₂ check karo. Paani baad mein paudhe ko.
Wow!
Hydraulic press mein ek bachche ka zor bhi kai tonne ka bal bana sakta hai — bas bade piston ko bahut kam doori chalni padti hai!
3 sawaal
- Hydraulic lift mein A₂ = 50 A₁ ho toh output bal kitna?
Jawab dekho
F₂ = 50 F₁. F₁/A₁ = F₂/A₂, isliye F₂ = F₁ × (A₂/A₁) = 50 F₁.
- Tyre ka gauge kya naapta hai?
Jawab dekho
P − P₀ (gauge pressure). Gauge pressure = absolute pressure minus vayumandaliya dabaav.
- Hydrostatic paradox kya kehta hai?
Jawab dekho
Ek hi gehrai par alag shape ke bartanon mein tali ka dabaav barabar. P = P₀ + ρgh; dabaav gehrai par tika hai, shape ya kul maatra par nahi.
NCERT se jodo: NCERT Class 11 Physics — mechanical properties of fluids: pressure, Pascal ka niyam, hydraulic machines (idea in words)