1.

Derive the relationship between the velocity v of water which depends on the density of water rho and the acceleration due to gravity g

Answer»

CORRECT QUESTION:

DERIVE the relationship between the velocity v of water which depends on wavelength, density of water RHO and the acceleration due to gravity g.

ANSWER:

  • \sf v = <klux>K</klux>\ \sqrt{\lambda\ g}

GIVEN:

  • Velocity of water which depends on wavelength, density of water and the acceleration due to gravity.

TO FIND:

  • Relationship between wavelength, density and gravity.

EXPLANATION:

\boldsymbol{[ v ] = [ M^0 \ L \ T^{-1}]}

\boldsymbol{[\lambda] = [M^0\ L^1\ T^0]}

\boldsymbol{[\rho] = [M^1\ L^{-3}\ T^0]}

\boldsymbol{[g] =[M^0\ L \ T^{-2}]}

\sf v\propto \lambda^a \ \rho^b \ g^c

\sf v = k\  \lambda^a \ \rho^b \ g^c

K is the constant of proportionality and has no unit and dimensions.

\boldsymbol{ [v]= [ \lambda]^a \ [\rho]^b \ [g]^c}

\boldsymbol{[\lambda]^{a} = [M^0\ L^1\ T^0]^{a}}

\boldsymbol{[\lambda]^{a} = [ L^a]}

\boldsymbol{[\rho] ^{b}= [M^1\ L^{-3}\ T^0]^{b}}

\boldsymbol{[\rho] ^{b}= [M^b\ L^{-3b}]}

\boldsymbol{[g]^{c} =[M^0\ L \ T^{-2}]^{c}}

\boldsymbol{[g]^{c} =[ L^{c} \ T^{-2c}]}

\boldsymbol{[ \lambda]^a \ [\rho]^b \ [g]^c = [ L^a] [M^b\ L^{-3b}][ L^{c} \ T^{-2c}]}

Add the power for same bases.

\boldsymbol{[ \lambda]^a \ [\rho]^b \ [g]^c =[M^b \ L^{a - 3b+c} \ T^{-2c}]}

\boldsymbol{[ M^0 \ L \ T^{-1}]=[M^b \ L^{a - 3b+c} \ T^{-2c}]}

Equate the powers for same bases.

\sf M^0 = M^b

\sf b = 0

\sf{T^{-1}=T^{-2c}}

\sf{-1= -2c}

\sf{c =  \dfrac{1}{2} }

\sf L  =  L^{a - 3b+c}

\sf a - 3b +{ \dfrac{1}{2} } = 1

\sf a -0 = { \dfrac{1}{2} }

\sf a = \dfrac{1}{2}

\large v = k\  \lambda^{ \frac{1}{2} } \ \rho^0 \ g^{ \frac{1}{2} }

\sf v = k\ \sqrt{\lambda\ g}



Discussion

No Comment Found

Related InterviewSolutions