Mechanical Properties Of Fluids(11th And 12th > Physics ) Questions and Answers
Explanation:-
Answer: Option D. -> Water flowing out through a hole in the side of a tank:
D
When water flows out of a hole in a tank, it is in contact with the edges of the hole over a very small area, and therefore viscosity effects are small
Explanation:-
Answer: Option D. -> 19.05 kg/m-s:
D
In this case the terminal velocity is upward. Since σ>ρ, the density of the air
inside the bubble may be neglected completely.
From equation
v=2a2(σ−ρ)ggη=2a2ρg9η⇒η=2a2ρg9v
where, a = 5mm, ρ=1.4×103kg/m3,v=4mm/s
∴η=2×25×10−6×1.4×103×9.89×4×10−3kg/m−s=19.05kg/m−s
Hence, (D) is correct.
Explanation:-
Answer: Option D. -> Water flowing out through a hole in the side of a tank:
D
When water flows out of a hole in a tank, it is in contact with the edges of the hole over a very small area, and therefore viscosity effects are small
Explanation:-
Answer: Option D. -> 0.0005:
D
A=(0.1)2=0.01m2, η=0.01 Poise = 0.001 decapoise (M.K.S. unit),
dv=0.1 m/s and F = 0.002 N
F=ηAdvdx ∴dx=ηAdvF=0.001×0.01×0.10.002=0.0005m
Explanation:-
Answer: Option A. -> 80 Kg:
A
Volume of log of wood V=massdensity=120600=0.2m3
Let x weight that can be put on the log of wood.
So weight of the body = (120+x)×10 N
Weight of displaced liquid = Vρg=0.2×103×10 N
The body will just sink in liquid if the weight of the body will be equal to the weight of displaced liquid.
(120+x)×10N=0.2×103×10 N
⇒x=80kg
Explanation:-
Answer: Option B. -> 1.94:
B
Apparent weight = V(ρ−σ)g=Mρ(ρ−σ)g
=M⟮1−σρ⟯g=2.1⟮1−0.810.5⟯g=1.94g N
=1.94 Kg−wt
Explanation:-
Answer: Option A. -> 2.5 cm:
A
The height of water in the tank becomes maximum when the volume of water flowing into the tank per second becomes equal to the volume flowing out per second. Volume of water flowing out per second
=Av=A√2gh ......(i)
Volume of water flowing in per second
=70 cm3/sec ......(ii)
From (i) and (ii) we get
A√2gh=70⇒1×√2gh=70
⇒1×√2×980×h=70
∴h=49001960=2.5 cm
Explanation:-
Answer: Option C. -> 1.0 m/s:
C
If the liquid is incompressible then mass of liquid entering through left end, should be equal to mass of liquid coming out from the right end.
∴M=m1+m2⇒Av1=Av2+1.5A.v
⇒A×3=A×1.5+1.5A.v⇒v=1m/s