Let pressure outside bubble be P₁, between two layers be P₂ and pressure inside bubble be P₃.
P₂ – P₁ = 2S/R
P₃ – P₂ = 2S/R
&re4; P₃ – P₁ = 4S/R
This shows that excess pressure just inside first layer is 2S/R while excess pressure completely inside bubble is 4S/R.

Bernoulli?s equation can be used for non-viscous, incompressible and steady laminar flow.

If tube is of insufficient length n contact angle changes and doesn?t let water overflow. The surface tension force balances weight of water risen.
2πrcos&ta;*S = πr² hρg.
Here, ta will be different from known value of contact angle for water and glass tube.

Barometer is a device used to measure air pressure. Odometer is a device used to measure distance travelled by a wheeled vehicle (it is speed indicator in your vehicle). Dynamometer is a device used to measure torque or rpm of an engine. Hydrometer is used to measure specific gravity of liquids. Also keep in mind that liquid used in a barometer is mercury.

Surface tension is defined as force per unit length or surface energy per unit area.
The unit is refore N/m.
Anor unit people use is J/m² (where J refers to joule, unit of energy).
But obviously it is equal to Nm/m² = N/m.

In case of liquids when temperature increases, viscosity decreases because it is result of molecular bonds (electromagnetic forces) between particles which weaken due to random motion brought about by increase in temperature. In case of gases, molecules vibrate more randomly, leading to more obstruction in path of bodies trying to move through it. And we interpret this increased obstruction as increased viscosity of gas.

P = F/3²
P = F/9
P? = 2F/1²
P? = 2F/1
P/P? = (F/9)/(2F/1)
= 1/18.

Given that area of tank is > > area of hole, we can use formula v = \(\sqrt{2gh}\). This shows that speed depends only on acceleration due to gravity and height of hole from surface.

When car is moving with constant velocity, points on same horizontal level will have same pressure.
So, P_A – P_B = 0.
When car moves with constant acceleration pressure difference between those two points will be ρaL,
as pressure difference will be responsible for providing acceleration to small fluid column of volume L*dA between points A & B
(where dA is an area of small element that we think of).

Surface tension, a surface phenomenon, is defined as force per unit length. It is a property of a liquid.
Let surface tension be ?S?.
We can say S = F1/2l and S = F2/l.
Therefore F1/2l = F2/l,
which implies F1/F2 = 2/1.