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# Test: Viscosity

## 10 Questions MCQ Test Machine Design | Test: Viscosity

Description
This mock test of Test: Viscosity for Mechanical Engineering helps you for every Mechanical Engineering entrance exam. This contains 10 Multiple Choice Questions for Mechanical Engineering Test: Viscosity (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Viscosity quiz give you a good mix of easy questions and tough questions. Mechanical Engineering students definitely take this Test: Viscosity exercise for a better result in the exam. You can find other Test: Viscosity extra questions, long questions & short questions for Mechanical Engineering on EduRev as well by searching above.
QUESTION: 1

### Viscosity is defined as the external resistance offered by a fluid to change its shape or relative motion of its parts.

Solution:

Explanation: It is an internal resisting force.

QUESTION: 2

### Stream line flow happens when intermediate layers move with velocities proportional to the square of distance from the stationary plate.

Solution:

Explanation: It is proportional to distance and not square of it.

QUESTION: 3

### Newton law of viscosity states that shear stress is proportional to rate of shear at any point in the fluid.

Solution:

Explanation: P/A proportional to U/h.

QUESTION: 4

Calculate the kinematic viscosity if Saybolt viscosity is 400cSt.

Solution:

Explanation: z=0.22t-[180/t] where t=400.

QUESTION: 5

Viscosity of lubricating oil decrease with increasing temperature.

Solution:

Explanation: Intermolecular forces decrease on the increase of temperature.

QUESTION: 6

Which of the following lubricant has least rate of change of viscosity w.r.t temperature.

Solution:

Explanation: Greater the VI, lesser is the rate of change w.r.t temperature.

QUESTION: 7

Which of the following are not true for petroff’s equation?

Solution:

Explanation: M=fWr=f(2prl)r, W=projected area of bearing x pressure.

QUESTION: 8

In hydrodynamic lubrication, film thickness remains unaffected by change in speeds.

Solution:

Explanation: As speed increases more and more lubricant is forces and pressure builds up thus separating the two surfaces. There is transition from thin film thick film.

QUESTION: 9

For a hydrostatic thrust bearing,
Thrust load=450kN, shaft speed=730rpm, shaft diameter=450mm, recess diameter=310mm, film thickness=0.15mm, viscosity of lubricant=160SUS and specific gravity=0.86.
Calculate supply pressure

Solution:

Explanation: P=2Wln(225/155)/[π(225²-155²)] N/mm².

QUESTION: 10

For a hydrostatic thrust bearing,
Thrust load=450kN, shaft speed=730rpm, shaft diameter=450mm, recess diameter=310mm, film thickness=0.15mm, viscosity of lubricant=160SUS and specific gravity=0.86.
Calculate flow requirement

Solution:

Explanation: Q=πPhᵌ/6µln(225/155) whereµ=z/10⁹ and z=0.86x[0.22×160-180/160]. µ=29.3 x 10¯⁹N-s/mm².