# Dimensional Analysis - Mechanical Engineering (MCQ) questions and answers

1)   Square root of the ratio of inertia force to elastic force is called as

a. Mach's Number
b. Cauchy's Number
c. Both a. and b.
d. None of the above
 Answer  Explanation ANSWER: Both a. and b. Explanation: No explanation is available for this question!

2)   Which of the following statements are true for dimensional analysis?

1. The functional relationship between dependent and non-dependent variables can be expressed into dimensionless terms by dimensional analysis
2. In model testing, it reduces the number of variables into three numbers
3. It is used to change the theoretical equation into dimensionless form
4. It helps to convert the units of quantities from one system to another system

a. (1), (2) and (3)
b. (2), (3) and (4)
c. (1), (3) and (4)
d. (1), (2), (3) and (4)
 Answer  Explanation ANSWER: (1), (2), (3) and (4) Explanation: No explanation is available for this question!

3)   The unit of physical quantity which does not depend on the unit of any other physical quantity is called as

a. independent dimension
b. fundamental dimension
c. core dimension
d. none of the above
 Answer  Explanation ANSWER: fundamental dimension Explanation: No explanation is available for this question!

4)   Which of the following is not a primary quantity?

a. Mass (M)
b. Temperature (θ)
c. Time (T)
d. None of the above
 Answer  Explanation ANSWER: None of the above Explanation: No explanation is available for this question!

5)   What are the dimensions of force?

a. [M L T – 2 ]
b. [M L T – 1 ]
c. [M L 2 T – 2 ]
d. [M L 2 T 2 ]
 Answer  Explanation ANSWER: [M L T – 2 ] Explanation: No explanation is available for this question!

6)   Which of the following quantities has the dimensions [M0 L0 T 0]

a. Density
b. Stress
c. Strain
d. Strain Rate
 Answer  Explanation ANSWER: Strain Explanation: No explanation is available for this question!

7)   Match the following physical quantities in Group 1 with their dimensions in Group 2.

1. Work done (Energy) (W) ----------------------------- A. [M L 2 T – 3 ]
2. Power (P) ------------------------------------------------ B. [M L – 1 T   – 1 ]
3. Momentum (M) ---------------------------------------- C. [M L 2 T – 2 ]
4. Modulus of elasticity (E) ----------------------------- D. [M L T – 1 ]
5. Dynamic viscosity (μ) --------------------------------- E. [M L – 1 T – 2 ]

a. 1-(C), 2-(A), 3-(D), 4-(E), 5-(B)
b. 1-(A), 2-(C), 3-(D), 4-(E), 5-(B)
c. 1-(C), 2-(A), 3-(E), 4-(B), 5-(D)
d. 1-(D), 2-(E), 3-(B), 4-(A), 5-(C)
 Answer  Explanation ANSWER: 1-(C), 2-(A), 3-(D), 4-(E), 5-(B) Explanation: No explanation is available for this question!

8)   Which of the following equations is not dimensionally homogeneous?
Consider standard symbols for quantities.

a. (Force) F = m x a
b. (Head Loss due to friction) hf = (f L V2) / (2 g d)
c. (Torque) T = F x Distance
d. None of the above
 Answer  Explanation ANSWER: None of the above Explanation: No explanation is available for this question!

9)   Which of the following is a dimensionless equation?

a. Reynold's equation
b. Euler's equation
c. Weber's equation
d. All of the above
 Answer  Explanation ANSWER: All of the above Explanation: No explanation is available for this question!

10)   Which of the following number is applicable in open hydraulic structure such as spillways, where gravitational force is predominant?

a. Reynold's Number
b. Euler's Number
c. Weber's Number
d. Froude's Number
 Answer  Explanation ANSWER: Froude's Number Explanation: No explanation is available for this question!