Check this................!!!!!!!!!!

JEE Main Discussion Forum › General Physics questions › Check this................!!!!!!!!!!

A barometer tube of negligible mass is suspended from a spring balance as shown. The mass of mercury in the tube is m and atmospheric pressure is p₀ . The cross section area of tube is A. What is the reading of spring balance ?
( my diagram is not that good.....pls manage [4])

#Physics #General Physics

UP 0 DOWN 0 0 8
Post on FacebookPost anonymously?

8 Answers

11

virang1 Jhaveri ·2009-03-08 22:53:31

mg + pA

UP 0 DOWN 0
Post on FacebookPost anonymously?

11

virang1 Jhaveri ·2009-03-08 22:53:47

Is it rite?

UP 0 DOWN 0
Post on FacebookPost anonymously?

11

virang1 Jhaveri ·2009-03-08 23:01:17

spring balance measure weight or mass?

UP 0 DOWN 0
Post on FacebookPost anonymously?

11

virang1 Jhaveri ·2009-03-08 23:05:40

i feel it measures weight.

Therefore mg is the weight of the mercury. The additional force by Pressure is pA

I feel therefore my answer is rite

UP 0 DOWN 0
Post on FacebookPost anonymously?

62

Lokesh Verma ·2009-03-08 23:15:00

Hint draw the FBD of the air column in the tube!

UP 0 DOWN 0
Post on FacebookPost anonymously?

11

virang1 Jhaveri ·2009-03-08 23:59:47

Cannot get it pls help sir.

UP 0 DOWN 0
Post on FacebookPost anonymously?

62

Lokesh Verma ·2009-03-10 03:53:34

pressure inside will be

P-ÏgH

=P-mg/A

difference in pressure on the top surface of the tube is P-(P-mg/A)

=mg/A

I think this should be the reading on the spring balance

UP 0 DOWN 0
Post on FacebookPost anonymously?

62

Lokesh Verma ·2009-03-10 03:53:56

because there is no other force acting anywhere on the tube..

UP 0 DOWN 0
Post on FacebookPost anonymously?

Your Answer

Basic Integral Calculus Operators Symbols Matrix Cases

√ √ || {} [] () → ~ ^ x x x → → ln log lg lim lim cos sin tan cot arcsin arccos arctan

∫ ∫ ∫ ∫ ∫ ∬ ∬ ∬ ∬ ∬ ∭ ∭ ∭ ∭ ∭ ⨌ ⨌ ⨌ ⨌ ⨌

∑ ∑ ∑ ∑ ∑ ∮ ∮ ∮ ∮ ∮ ∏ ∏ ∏ ∏ ∏ ∐ ∐ ∐ ∐ ∐

+ - × ÷ ± ∓ = ∪ ∩ ≠ ∼ ≈ ∅ ∀ ∃ ∈ ∋ ∝ ≤ ≥ ≃ ≅ ≡ < > ≪ ≫ ⊂ ∉ ⊃ ⊆ ⊇ ⇒ ⇐ ⇔ ⇒ ⇐ ⇔ ⇑ ⇓ ⇕ → ← ↔ → ← ↔ ↑ ↓ ↕ ↖ ↗ ↘ ↙ ↪ ↩ ⇀ ↼ ⇁ ↽

° ∂ ∞ α β γ δ θ λ μ ν ξ π ρ σ φ ω ε ƒ κ τ υ Γ Δ Λ Σ Π Ω