Two uniform solid balls of same density and if radii `r` and `2r` are dropped in air and fall vertically downwards. The terminal velocity of the ball with radius `r` is `1cms^-1`, then the terminal velocity of the ball of radius `2r` will be (neglect buoyant force on the balls.)A. `0.5cms^-1`B. `4cms^-1`C. `1cms^-1`D. `2cms^-1`

Two uniform solid balls of same density and if radii `r` and `2r` are

1.	Two uniform solid balls of same density and if radii `r` and `2r` are dropped in air and fall vertically downwards. The terminal velocity of the ball with radius `r` is `1cms^-1`, then the terminal velocity of the ball of radius `2r` will be (neglect buoyant force on the balls.)A. `0.5cms^-1`B. `4cms^-1`C. `1cms^-1`D. `2cms^-1`
Answer» Correct Answer - B At equilibrium `mg=6pietarv_0` or `rho(4pi)/(3)g=6pietarv` `(v_r)/(v_(2r))=((r )^2)/((2r)^2)` or `v_2r=(v_r)xx4=4(cm)/(s)`

Discussion

No Comment Found

Related InterviewSolutions

A film of water is formed between two straight parallel wires of length 10 cm each separated by `0.5cm` If their separation is increased by `1mm` while still maintaining their parallelism, how much work will have to be done (Surface tension of water `=7.2xx10^-2(N)/(m)`)A. `7.22xx10^-6Joule`B. `1.44xx10^-5joule`C. `2.88xx10^-5joule`D. `5.76xx10^-5joule`
A ball falling in a lake of depth `200 m` shows a decrease of `0.1% ` in its volume at the bottom. The bulk modulus of elasticity of the material of the ball is (take `g = 10 ms^(-2)`)A. `10^8`B. `2xx10^8`C. `10^9`D. `2xx10^9`
If pressure at half the depth of a lake is equal to 2//3 pressure at the bottom of the lake then what is the depth of the lake ?A. `10m`B. `20m`C. `60m`D. `30m`
The work per unit volume to stretch the length by `1%` of a wire with cross sectional area of `1mm^2` will be. `[Y=9xx10^(11)(N)/(m^2)`]A. `9xx10^11J`B. `4.5xx10^7J`C. `9xx10^7J`D. `4.5xx10^11J`
The radii of the two columne is U-tube are `r_(1)` and `r_(2)(gtr_(1))`. When a liquid of density `rho` (angle of contact is `0^@))` is filled in it, the level different of liquid in two arms is h. The surface tension of liquid is `(g=` acceleration due to gravity)A. `(rho gh r_(1)r_(2))/(2(r_(2) - r_(1)))`B. `(rho gh (r_(2) - r_(1)))/(2r_(1) r_(2))`C. `(2 (r_(2) - r_(1)))/(rho gh r_(1) r_(2))`D. `(rho gh)/(2(r_(2) - r_(1)))`
A long glass capillary (radius R) is taken out of liquid (surface tension S and density `rho`) in vertical position. Angle of contact everywhere is zero. Atmospheric pressure is `P_(0)`. It is observed that the capillary retains some liquid. The length of liquid column retained in the capillary isA. `(3 S)/(rho Rg)`B. `(2S)/(rho Rg)`C. `(4S)/(rho Rg)`D. zero
A long glass capillary (radius R) is taken out of liquid (surface tension S and density `rho`) in vertical position. Angle of contact everywhere is zero. Atmospheric pressure is `P_(0)`. It is observed that the capillary retains some liquid. The radius of curvature of meniscus at the bottom of tube isA. BB. `oo`C. `R//2`D. `R//3`
A capillary tube of radius r is lowered into a liquid of surface tension T and density `rho`. Given angle of contact `=0^(@)`. What is the potential energy acquired by the liquid in the capillary?A. `(pi T^(2))/(2 rho g)`B. `T^(2)/(2 rho g)`C. `T^(2)/(rho g)`D. `(2 pi T^(2))/(rho g)`
A capillary tube of radius r is lowered into a liquid of surface tension T and density `rho`. Given angle of contact `=0^(@)`. The work done by surface tension will beA. `(pi T^(2))/(rho g)`B. `(4 pi T^(2))/(rho g)`C. `(T^(2))/(rho g)`D. `(2T^(2))/(rho g)`
A cylinder of mass m and density `rho` hanging from a string is lowered into a vessel of cross-section area s containing a liquid of density `sigma (lt rho)` unit it is fully immersed. The increase in pressure at the bottom of the vessel isA. `(m rho g)/(sigma s)`B. `(mg)/(s)`C. `(m sigma g)/(rho s)`D. zero

Discussion

No Comment Found

Related InterviewSolutions

Reply to Comment