The speed of a flywheel is to be measured using stroboscope for single mark. After setting 2800 rpm on the stroboscope, a stationary picture of 4 marks is observed. What will be the speed of flywheel?

Explanation:

Stroboscope:

• A stroboscope is an instrument used to make a cyclically moving object appear to be slow-moving or stationary. The stroboscope emits a flashing light at a certain frequency, and when this frequency matches the frequency of the moving object's rotation, the object appears stationary. This principle is used to measure the speed of rotating objects such as flywheels.

Given:

• Stroboscope setting (n_s): 2800 rpm
• Number of stationary marks observed: 4

The actual speed of the flywheel is determined by the ratio of the stroboscope setting to the number of stationary marks observed. This is because the stationary picture is observed when the frequency of the stroboscope flashes matches the frequency of the flywheel's rotation at certain intervals.

Mathematically, the relationship is given by:

n_f = n_s / (Number of stationary marks)

Substituting the given values:

n_f = 2800 rpm / 4

n_f = 700 rpm

Therefore, the speed of the flywheel is 700 rpm.