Honey. Honey flows slower than oil. So it has greater viscosity.

The instruments Manometer, Bourdon gauge help to pressure of a fluid.

i) When a kicking force is exerted on a football at rest, it raises.
ii) When a pushing force is applied on a box at rest it moves.

From Boyle's law :- P α 
Initial Pressure P₁  = atmospheric pressure + pressure of liquid cloumn
= Hρg + Hρg
Where h 2 depth of the pond
H 2 Assume 10m of water
V₁ = \(\frac { 4 }{ 3 } \pi \)r³ ; P₂ = Hρg
V₂ = \(\frac { 4 }{ 3 } \pi \)(3r)³ = \(\frac { 4 }{ 3 } \pi \)(27r³)
P₁V₁ = P₂V₂ 

​​​​​​​h+10 =10x27
h =270-10
depth of the pond, h = 260m

i)Pour soap powder or oil into the sea near their ship.
ii) It decreases the surface tension of sea water.
iii) It reduces the impact of the violent water current.

Experiment:
i) Arrange some notebooks one over the other to form a platform on a table.
ii) Keep a wide scale, as a slide, such that one of its ends rests on the pile of books:
iii) Take different kinds of materials like cotton cloth, plastic paper, newspaper, writing pad etc.
iv) Place some glass marbles in a bowl placed on the table.
v) First, keep a rectangular piece of paper near the end of the scale which is in contact with the table.
vi) Now release a glass marble from the top end of the scale such that it rolls down the scale.
vii) Allow the marble to roll over the piece of paper and finally, come to rest.
viii) Measure the distance travelled by the marble over the paper using the meter scale.
ix) Replace the rolling surface by placing the plastic sheet, wooden plank, cotton cloth etc.
x) In each trial measure the distance travelled by the glass marble.
xi) Tabulate the distance covered by the marble over each surface.

Inference:
The marble covers a lesser distance over the cotton cloth in comparison with the distance it covers over the glass plate.
Reason:
i) A rough surface like the cotton cloth offers more frictional force. So the marble moves slowly and cover a minimum distance.
ii) The smooth surface of glass, offers lesser friction. So, the glass marble travels a greater distance over it.
Result:
i) The effect of the force of friction increases as the roughness of the surface increases.
ii) Thus friction depends on the nature of a surface.

i) No, there is no possibility of making a special device to measure the magnitude of friction directly. The magnitude of friction is directly proportional to irregular surface of contact, and the magnitude of the force exerted on it.
ii) The magnitude of friction of a body remains changing and self adjusting. So it cannot be measured directly
iii) With Tribometer we can calculate co-efficient of friction (u) and then we can calculate the magnitude of friction from it.