Imp questions with solution.

Q1)

*Here  iron piece is suspended in the water and the iron piece doesn't touch any side of the  bucket. 

1) But, whenever a body is floating on the water surface or submerged in the water, there exists buoyancy forces which acts vertically upwards 

2) For this action there shall be equal and opposit reaction, which acts vertically downwards. 

3) and this reaction causes reading in spring balance. 

So answer is A

In Q1 tension in string can be asked and is very important concept for both GATE and IES.

***4) Tension in string is (T)= mg-Fb.

(Given in above figure )

 Here 

Fb is buoyancy, 

m is mass of the body or iron piece. 

Q2).

Solution
Since, boundary layer thickness is directly proportional to square root of distence from leading edge.
Where
S1(2mm) is boundary layer thickness at distence Lx1(2m) from leading edge
S2(? ) Boundary layer thickness at Lx2(4m)
So
(S1/S2)=(Lx1/Lx2)^(1/2)
(2/S2)=(2/4)^(1/2)
S2=2×2^(1/2)
S2=2×1.414
S2=2.828mm.(answer)

So option (B) is right answer.

IF THIS CONTENT HAS HELPED You THEN SHARE IT TO YOUR MECHANICAL FRIENDS.

By RAJKUMAR CLASSES