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A turning moment diagram is a graphical representation that illustrates the variation of torque produced by an engine or motor with respect to the angle of rotation of the output shaft - AQA - A-Level Physics - Question 2 - 2019 - Paper 6
Question 2
A turning moment diagram is a graphical representation that illustrates the variation of torque produced by an engine or motor with respect to the angle of rotation ... show full transcript
Worked Solution & Example Answer:A turning moment diagram is a graphical representation that illustrates the variation of torque produced by an engine or motor with respect to the angle of rotation of the output shaft - AQA - A-Level Physics - Question 2 - 2019 - Paper 6
Step 1
State what is represented by the area between the curve and the angle axis for a turning moment diagram.
Answer
The area between the curve and the angle axis in a turning moment diagram represents the work done or energy output over a complete cycle of the engine. It indicates the amount of torque available during the rotation of the shaft.
Step 2
Discuss why, to drive this machine, the diesel engine would need to be fitted with a flywheel.
Answer
To drive the machine effectively, the diesel engine must be fitted with a flywheel for several reasons.
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Electric Motor and Flywheel: The electric motor does not require a flywheel because it provides a more consistent torque output throughout its operation. Unlike diesel engines, electric motors maintain smooth and continuous power delivery due to their design and operating principles.
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Torque Variation in Diesel Engine: The torque produced by a diesel engine varies significantly over one cycle due to its operational phases, including induction, compression, power, and exhaust. During these phases, there are moments when torque is zero, particularly during the exhaust stroke when the engine is expelling spent gases. This fluctuation can lead to jerky motion, which is not ideal for applications requiring steady torque.
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Influence of Flywheel's Moment of Inertia: The flywheel helps smooth out these fluctuations by storing energy when torque is high and releasing it when torque drops. The larger the moment of inertia of the flywheel, the more effectively it can dampen variations in torque. By doing so, it ensures a more even and steady power output to the output shaft, enhancing the performance of the machine.