hydrostat

a balll of density ρ0 falls from rest from a point P onto the surface of a liquid of density ρ in time T. It enters the liquid, stops, moves up n returns to P in a total time 3T. Neglect the viscosity, surface tension and splashing. the ratio ρ/ρ0 is :::

A) 1.5 B) 2 C) 3 D) 4

9 Answers

1
ANKIT MAHATO ·

practically not possible !! X~)

1
skygirl ·

[3]

1
ANKIT MAHATO ·

2..

1
ANKIT MAHATO ·

ρ/ρ0 = 2 .. in side the liquid u will get that T = T/(ρ/ρ0 - 1)
possible if this = 2 ..

62
Lokesh Verma ·

force in the upward direction is given by
(ρ-ρ0)Vg
V is the volume

Force = ma
(ρ-ρ0)Vg = ρ0Va
a= (ρ/ρ0-1)g

Velocity when entering the fluid = gT
final displacement = 0
s= ut+1/2at2
s= 0, a=(ρ/ρ0-1)g and t= 3T, u = -gT

ut+1/2at2
2u=at
2gT=(ρ/ρ0-1)g (T) {Here 2T is removed because it is the time in air again!}

2=(ρ/ρ0-1)
ρ/ρ0 = 3

21
tapanmast Vora ·

balll of density ρ0 falls from rest from a point P

MEANS p is in air, then how :

moves up n returns to P

1
ANKIT MAHATO ·

something i want to share ... if the ball takes time T to fall to a point P then again from P to T while it was returning it takes time T .. . so inside the liq it takes 2T .. that implies while going down the liquid it will take time T so gT - (ρ/ρ0 - 1)gT = 0 ... and i think my answer is correct !!!

62
Lokesh Verma ·

yes ankit.. i correct it already :)

may be just when you were typing this message :)

1
ANKIT MAHATO ·

yup bhaiya !! [50] deleted my post !

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