back to directory
NEET PHYSICSMechanical Properties of FluidEasy

Question

The terminal velocity of a copper ball of radius 5 mm5 \text{ mm} falling through a tank of oil at room temperature is 10 cm s110 \text{ cm s}^{-1}. If the viscosity of oil at room temperature is 0.9 kg m1 s10.9 \text{ kg m}^{-1} \text{ s}^{-1}, the viscous drag force is:

A

8.48×103 N8.48 \times 10^{-3} \text{ N}

B

8.48×105 N8.48 \times 10^{-5} \text{ N}

C

4.23×103 N4.23 \times 10^{-3} \text{ N}

D

4.23×106 N4.23 \times 10^{-6} \text{ N}

Step-by-Step Solution

According to Stokes' Law, the viscous drag force (FF) acting on a spherical body of radius rr moving with terminal velocity vv in a fluid of viscosity η\eta is given by the formula: F=6πηrvF = 6\pi \eta r v

Given values: Viscosity, η=0.9 kg m1 s1\eta = 0.9 \text{ kg m}^{-1} \text{ s}^{-1} Radius, r=5 mm=5×103 mr = 5 \text{ mm} = 5 \times 10^{-3} \text{ m}

  • Velocity, v=10 cm s1=0.1 m s1v = 10 \text{ cm s}^{-1} = 0.1 \text{ m s}^{-1}

Calculation: Substitute the values into the formula: F=6×3.14159×0.9×(5×103)×0.1F = 6 \times 3.14159 \times 0.9 \times (5 \times 10^{-3}) \times 0.1 F=6×0.9×0.5×103×3.14159F = 6 \times 0.9 \times 0.5 \times 10^{-3} \times 3.14159 F=5.4×5×104×3.14159F = 5.4 \times 5 \times 10^{-4} \times 3.14159 F=2.7×103×3.14159F = 2.7 \times 10^{-3} \times 3.14159 F8.48×103 NF \approx 8.48 \times 10^{-3} \text{ N}

Exam Context & Concepts Covered

This question aligns with the NEET PHYSICS syllabus, specifically targeting concepts from Mechanical Properties of Fluid. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

PHYSICSMechanical Properties of Fluidterminalvelocitycopperradiusfalling

More Mechanical Properties of Fluid Questions

View all

A rectangular film of liquid is extended from $(4 \text{ cm} \times 2 \text{ cm})$ to $(5 \text{ cm} \times 4 \text{ cm})$. If the work done is $3 \times 10^{-4} \text{ J}$, then the value of the surface tension of the liquid is:

A.$0.250 \text{ Nm}^{-1}$
B.$0.125 \text{ Nm}^{-1}$
C.$0.2 \text{ Nm}^{-1}$
D.$8.0 \text{ Nm}^{-1}$
EasySolve

A small hole of an area of cross-section $2 \text{ mm}^2$ is present near the bottom of a fully filled open tank of height $2 \text{ m}$. Taking $g = 10 \text{ m/s}^2$, the rate of flow of water through the open hole would be nearly:

A.$6.4 \times 10^{-6} \text{ m}^3/\text{s}$
B.$12.6 \times 10^{-6} \text{ m}^3/\text{s}$
C.$8.9 \times 10^{-6} \text{ m}^3/\text{s}$
D.$2.23 \times 10^{-6} \text{ m}^3/\text{s}$
EasySolve

In a U-tube, as shown in the figure, the water and oil are in the left side and right side of the tube respectively. The height of the water and oil columns are 15 cm and 20 cm respectively. The density of the oil is: [take ρ_water = 1000 kg/m^3]

A.1200 kg/m^3
B.750 kg/m^3
C.1000 kg/m^3
D.1333 kg/m^3
EasySolve

A U-tube with both ends open to the atmosphere is partially filled with water. Oil, which is immiscible with water, is poured into one side until it stands at a distance of $10 \text{ mm}$ above the water level on the other side. Meanwhile, the water rises by $65 \text{ mm}$ from its original level (see diagram). The density of the oil is:

A.$650 \text{ kg m}^{-3}$
B.$425 \text{ kg m}^{-3}$
C.$800 \text{ kg m}^{-3}$
D.$928 \text{ kg m}^{-3}$
MediumSolve

Which of the following statements is not true?

A.The coefficient of viscosity is a scalar quantity.
B.Surface tension is a scalar quantity.
C.Pressure is a vector quantity.
D.Relative density is a scalar quantity.
EasySolve

The heart of a man pumps $5 \text{ L}$ of blood through the arteries per minute at a pressure of $150 \text{ mm}$ of mercury. If the density of mercury is $13.6 \times 10^3 \text{ kg/m}^3$ and $g = 10 \text{ m/s}^2$, then the power of heart in watt is:

A.1.7
B.2.35
C.3
D.1.5
MediumSolve

Water rises to a height $h$ in a capillary tube. If the length of the capillary tube above the surface of water is made less than $h$, then:

A.water rises upto the tip of capillary tube and then starts overflowing like a fountain
B.water rises upto the top of capillary tube and stays there without overflowing
C.water rises upto a point a little below the top and stays there
D.water does not rise at all
EasySolve

A liquid does not wet the solid surface if the angle of contact is:

A.equal to 45°
B.equal to 60°
C.greater than 90°
D.zero
EasySolve

This neet physics practice question is part of the TopperSquare free question bank. TopperSquare offers 15,000+ chapter-wise NEET MCQs across Physics, Chemistry, and Biology with detailed step-by-step explanations, full mock tests, NEET PYQs (2010–2024), and an AI-powered performance analytics dashboard. browse all neet practice questions → · practice physics sets →