MCQOPTIONS
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MCQOPTIONS
This section includes 9 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Operations knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Which component of the total force is perpendicular to the direction of motion? What are the dimensions of this component? |
| A. | Lift, MLT<sup>-1</sup> |
| B. | Drag MLT |
| C. | Drag, MLT<sup>-2</sup> |
| D. | Lift, MLT<sup>-2</sup> |
| Answer» E. | |
| 2. |
Calculate the drag force on a ball of diameter of 80mm, flowing through air. The density of air is 1.25 kg/m3 and the ball flows with a velocity of 7m/s. The Reynolds number is 3730. |
| A. | 0.077 N |
| B. | 76969 N |
| C. | 0.011 N |
| D. | 10995 N |
| Answer» B. 76969 N | |
| 3. |
Let FG be the gravitational force, FD be the drag force and FB be the buoyant force. Which of the following best describes the relation between these forces when a sphere falls into a fluid with terminal velocity? |
| A. | F<sub>G</sub> + F<sub>D</sub> = F<sub>B</sub> |
| B. | F<sub>G</sub> + 2F<sub>B</sub> = F<sub>D</sub> |
| C. | 2F<sub>B</sub> + F<sub>D</sub> = F<sub>G</sub> |
| D. | F<sub>B</sub> + F<sub>D</sub> = F<sub>G</sub> |
| Answer» E. | |
| 4. |
What are the dimensions of drag coefficient? |
| A. | Dimensionless |
| B. | MLT<sup>-2</sup> |
| C. | ML<sup>-3</sup> |
| D. | L |
| Answer» B. MLT<sup>-2</sup> | |
| 5. |
The total drag is a sum of the skin drag and the pressure drag. Which among of the following options, states the correct formula for skin drag and pressure drag?
|
| A. | 2 DU, 2 DU |
| B. | 1 DU, 2 DU |
| C. | 2 DU, DU |
| D. | 3 DU, DU |
| Answer» D. 3 DU, DU | |
| 6. |
Under which circumstances is the Oseen formula valid for drag coefficient? |
| A. | When the Reynolds number is between 0.3 and 5 |
| B. | When the Reynolds number is between 0.2 and 4 |
| C. | When the Reynolds number is between 0.3 and 4 |
| D. | When the Reynolds number is between 0.2 and 5 |
| Answer» E. | |
| 7. |
Under which condition, is the Cunningham correction factor applicable for very small particles? |
| A. | When particle size is far greater than the gas mean free path |
| B. | When particle size is far lesser than the gas mean free path |
| C. | When particle size becomes comparable to the gas mean free path |
| D. | Cunningham factor is applicable for small particles under all conditions |
| Answer» D. Cunningham factor is applicable for small particles under all conditions | |
| 8. |
What is the value of CD corresponding to a Reynold s number between 5 and 1000? |
| A. | 0.3 |
| B. | 0.4 |
| C. | 0.2 |
| D. | 0.1 |
| Answer» C. 0.2 | |
| 9. |
Which of the following is the correct form of Stoke s law?
|
| A. | C<sub>D</sub> = 24 / N<sub>Re</sub> |
| B. | C<sub>D</sub> = 24 * N<sub>Re</sub> |
| C. | C<sub>D</sub> = 18 / N<sub>Re</sub> |
| D. | C<sub>D</sub> = 18 * N<sub>Re</sub> |
| Answer» B. C<sub>D</sub> = 24 * N<sub>Re</sub> | |