Briefly answer the following questions In the rotation speed

Briefly answer the following questions: In the rotation speed measurement by a stroboscope, why to use the \"double\" or \"half\" function in frequency adjustment of stroboscope? In the rotation speed measurement by a tachometer, what is the main purpose to compare the pdf of rotating speed against Gaussian distribution? What is the difference between the standard equation of a given type of thermocouple (with a reference point at 0 degree C) and the equation of the same thermocouple with a floating reference point at the ambient temperature (say, 25 degree C)? You may use a schematic graph or example to explain. Why does a thermocouple do not need calibration (and hence used as a standard temperature to calibrate other temperature methods)? Why is a commercial thermocouple typically more reliable than a home-made one (assuming the same thermocouple materials are used)? A truck-load (L) is determined by the weight difference between an unloaded truck (W_1) and the one with load (W_2). (a) If the weights are measured by the same load cell with the same absolute error margin (plus or minus u_w), what is the uncertainty of L? (b) If the error margin of load-cell measurement is determined by a fixed percentage (say, plus or minus 1%) of the nominal weight, what is the uncertainty of L? The coefficients of a thermistor, alpha and beta, can be determined either by a two-point calibration (e.g., R_1 at T_1 = 0 degree C and R_2 at T_2 = 100 degree C) or by a curve fitting using a series of measurements {R_i, T_i} (i = 1, N}. Which one is more accurate? Why?

Solution

in the rotational speed measuring by a stroboscope to measure the rotation speed the stroboscope use double or half function bcz the frequency will chances by increasing or decreasing the speed

in the rotation speet tachometer; the main perpose to compare the pdhf is to know the exact speed.