Lab_8

 

 

 

New Problems reloads the page with new variable values in all questions. You must do this after grading the test to rework it another time.
Make sure to calculate your answers in SI units unless specified otherwise .

 

 

 

 

1) You measure the mass of a string to be grams, and the length of the string to be cm. The string runs over a pulley and has grams suspended from it as shown in the figure above. What is the velocity of a traveling wave on the string (Ch10 sheet 20) ? Indicate with a positive (negative) sign whether the string length to be measured extends from points A to B (A to C).

 

2) You vary the frequency, which excites standing waves on a string and record it every time a standing wave pattern is observed. You plot the frequencies  versus the number n of half waves observed and measure the slope of the linear graph you obtain to be Hz. You relate the slope to the traveling wave velocity v (Ch10 sheet 19) and calculate v from the slope and the string length of cm. What is the value of v ? Indicate with a positive (negative) sign whether the string length to be measured extends from points A to B (A to C).

 

3) 1) You measure the mass of a string to be grams with an error of 0.1 grams, and the length of the string to be cm with an error of 2 cm. The string runs over a pulley and has grams suspended from it as shown in the figure above. You neglect the error of the suspended mass. What is the absolute error of the traveling wave velocity on the string (Ch10 sheet 20) ? (Hint: calculate the relative error of the linear mass density m=m/L using equation (7) of "Error and Uncertainty" ("EU"). Then write the wave velocity v in the form  (since you neglect the error of the suspended mass and hence the error of the string tension), and use equation (8) in "EU" to calculate the relative error of v. Finally change the relative error of v into the absolute error of v)


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