Final answer:
The indirect method is used to measure backlash when gears are not easily accessible or when the gear teeth are very small. This involves measuring the gear or shaft movement, not the gear teeth themselves. Torque relates to angular acceleration rather than angular velocity, requiring more information to determine the change in angular velocity.
Step-by-step explanation:
The method of measuring backlash referred to in the question is likely the indirect method. This method is typically used when gears are not easily accessible, or when the gear teeth are very small. Measuring backlash is essential for assessing the health of a gearing system, since excessive backlash can lead to gear damage, increased wear, and noise.
The indirect method involves measuring the movement of the gear or the shaft to which it is attached, without direct measurement of the gear teeth. This can be accomplished using dial indicators, lasers, or other measurement tools that do not require physical access to the gear teeth themselves.
To answer the unrelated segment from the question about angular velocity and torque on a fishing reel, we know that torque is related to the angular acceleration, not the angular velocity directly.
Therefore, knowing only the increase in torque does not provide a measure of angular velocity without considering other factors like the moment of inertia and any existing angular velocities.