# Fluid Mechanics Questions and Answers – Model Analysis

This set of Fluid Mechanics Multiple Choice Questions & Answers (MCQs) focuses on “Model Analysis”.

1. What is a model analysis?
a) A small-scale replica
b) Actual structure
c) Theory structure.

Explanation: Model analysis is defined as a small-scale replica of the actual structure. Model analysis need not be smaller all the time. They can even be larger than the prototype.

2. What is a prototype?
a) A small-scale replica
b) Actual structure
c) Theory structure.

Explanation: Prototype is the actual structure that needs to be constructed. For a better understanding of the model, we prepare a model analysis. They can even be larger than the prototype.

3. Advantage of a model analysis is_________
a) Performance cannot be predicted
b) The relationships between the variable cannot be obtained
c) Shear stress to thermal diffusivity
d) Alternative designs can be predicted

Explanation: One of the major advantages of the model analysis is that we can predict the alternative designs. It can also predict the performance of the machine in advance.

4. Why do we need a model analysis?
a) For determining the dimensions
b) To provide a safe design
c) To check the shear stress
d) To check the thermal diffusivity

Explanation: One of the major advantages of the model analysis is that we can predict the alternative designs. It provides the safest design in the most economical way.

5. The similarity between the motion of model and prototype is_________
a) Dynamic similarity
b) Potential similarity
c) Kinematic similarity
d) Design similarity

Explanation: Kinematic similarity is defined as the similarity between motion of the model and the prototype. It exists in between the model and prototype. The points in the model and prototype are of the same magnitude.

6. The similarity between the forces of model and prototype is ________
a) Dynamic similarity
b) Potential similarity
c) Kinematic similarity
d) Design similarity

Explanation: Dynamic similarity is defined as the similarity between forces of a model and the prototype. It exists in between the model and prototype. The points in the model and prototype are of the same magnitude.

7. Which among these forces does not act in a moving fluid?
a) Inertial force
b) Viscous force
c) Gravity force
d) Drag

Explanation: Drag does not take place in moving fluids. Moving fluids are restricted by a viscous force and move along an inertial force. The gravitational force tends to act perpendicular to the fluid surface.

8. What is the formula for elastic force?
a) Elastic stress/area
b) Elastic strain/area
c) Elastic stress*area
d) Elastics stress* Elastic strain

Explanation: Elastic force is a force that is developed by a material to retain to its original position. It regains its shape after a period of time. When an elastic material is compressed or stretched, it develops an elastic force.

9. For a dynamic similarity between a model and a prototype, the ratio of their forces in the model and the prototype must be equal.
a) True
b) False

Explanation: For a dynamic similarity between a model and a prototype, the ratio of their forces in the model and the prototype must be equal. It means that the dynamic similarity between a model and a prototype must be the same.