The terminal velocity of a copper ball of radius $2.0 \;mm$ falling through a tank of oll at $20\,^{\circ} C$ is $6.5 \;cm s ^{-1} .$ Compute the viscosity of the oil at $20\,^{\circ} C .$ Density of oil is $1.5 \times 10^{3} \;kg m ^{-3},$ density of copper is $8.9 \times 10^{3} \;kg m ^{-3}$
Easy
Download our app for free and get started
We have $v_{ t }=6.5 \times 10^{-2} ms ^{-1}, a=2 \times 10^{3} m$
$g =9.8 ms ^{-2}, \rho=8.9 \times 10^{3} kg m ^{-3}$
$\sigma =1.5 \times 10^{3} kg m ^{-3}$
$\eta =\frac{2}{9} \times \frac{\left(2 \times 10^{-3}\right)^{2} m ^{2} \times 9.8 m s ^{-2}}{6.5 \times 10^{-2} m s ^{-1}} \times 7.4 \times 10^{3} kg m ^{-3}$
$=9.9 \times 10^{-1}\, kg \,m ^{-1} \,s ^{-1}$
Download our appand get started for free
Experience the future of education. Simply download our apps or reach out to us for more information. Let's shape the future of learning together!No signup needed.*
Similar Questions
- 1An ideal fluid flows (laminar flow) through a pipe of non-uniform diameter. The maximum and minimum diameters of the pipes are $6.4 \;\mathrm{cm}$ and $4.8 \;\mathrm{cm},$ respectively. The ratio of the minimum and the maximum velocities of fluid in this pipe is:View Solution
- 2View SolutionThe Working of an atomizer depends upon
- 3A steel wire is suspended vertically from a rigid support. When loaded with a weight in air, it extends by $l_a$ and when the weight is immersed completely in water, the extension is reduced to $l_w$. Then the relative density of material of the weight isView Solution
- 4A sphere is dropped under gravity through a fluid of viscosity $\eta$ . If the average acceleration is half of the initial acceleration, the time to attain the terminal velocity is ($\rho$ = density of sphere ; $r$ = radius)View Solution
- 5A flat plate of area $10\,cm^2$ is separated from a large plate by a layer of glycerine $1\, mm$ thick. If the coefficient of viscosity of glycerine is $20$ poise, the force required to keep the plate moving with a velocity of $1\,cm/sec$ is .......... $dyne$View Solution
- 6The density of the atmosphere at sea level is $1.29 \;kg / m ^{3} .$ Assume that it does not change with altitude. Then how high (in $km$) would the atmosphere extend?View Solution
- 7A rectangular block is $5 cm × 5 cm × 10cm$ in size. The block is floating in water with $ 5 cm $ side vertical. If it floats with $10 cm $ side vertical, what change will occur in the level of water?View Solution
- 8There is a $1$ $mm $ thick layer of glycerine between a flat plate of area $100$ $cm^2$ $\&$ a big fixed plate. If the coefficient of viscosity of glycerine is $1.0$ $kg/m^{-s}$ then ....... $N$ force is required to move the plate with a velocity of $7$ $cm/s$ ?View Solution
- 9Assume that, the drag force on a football depends only on the density of the air, velocity of the ball and the cross-sectional area of the ball. Balls of different sizes but the same density are dropped in an air column. The terminal velocity reached by balls of masses $250 \,g$ and $125 \,g$ are in the ratioView Solution
- 10A rectangular block is $5 cm × 5 cm × 10cm$ in size. The block is floating in water with $ 5 cm $ side vertical. If it floats with $10 cm $ side vertical, what change will occur in the level of water?View Solution