Engineering Questions with Answers - Multiple Choice Questions

# Machine Dynamics MCQ – Turning Moment Diagram for a Single Cylinder Double Acting Steam Engine

1 - Question

In the figure given below, the quantity represented by the arrow is known as ___________ a) Maximum Torque
b) Minimum Torque
c) Maximum Force
d) Mean resisting torque

Explanation: In a turning moment diagram given above, the line pointed out by the arrow is the value of mean torque and hence it is called mean resisting torque.

2 - Question

Turning moment is maximum when the crank angle is 90 degrees.
a) True
b) False

Explanation: Referring the turning moment diagram for a single cylinder double acting steam engine, the minimum values occur at 0, 180 and 360 degrees and maximum values occur at 90 and 270 degrees.

3 - Question

The curve abc in figure below is known as _________ a) Instroke
b) Outstroke
c) Positive couple
d) Negative couple

Explanation: In the given figure, the curve during the curve abc there is an ascent in the motion. The ascent of motion is known as outstroke thus curve abc is called outstroke.

4 - Question

The curve cde in figure below is known as _________ a) Instroke
b) Outstroke
c) Positive couple
d) Negative couple

Explanation: In the given figure, the curve during the curve cde there is a descent in the motion. The descent of motion is known as intstroke, thus curve cde is called instroke.

5 - Question

When engine torque is more than mean resisting torque, then the flywheel _______
a) Has uniform velocity
b) Has 0 velocity
c) Has acceleration
d) Has retardation

Explanation: When the difference between T-Tmean is positive the work is done by the steam and the crankshaft accelerated which results in acceleration of flywheel.

6 - Question

When engine torque is less than mean resisting torque, then the flywheel _______
a) Has uniform velocity
b) Has 0 velocity
c) Has acceleration
d) Has retardation

Explanation: When the difference between T-Tmean is negative the work is done on the steam and the crankshaft decelerates which results in retardation of flywheel.

7 - Question

Area of the turning moment diagram represents _______
a) Work done
b) Work done per revolution
c) Power generated
d) Power generated per revolution

Explanation: Since the work done is the product of the turning moment and the angle turned, therefore the area of the turning moment diagram represents the work done per revolution.

8 - Question

In actual practice, engine is assumed to work against the mean resisting torque.
a) True
b) False