Clip of the Week!

It’s Wednesday and it’s time for Clip of the Week!

This week’s Clip goes to violinist Rachel Arnesen. Rachel has her Senior recital this weekend and will be performing the Prokofiev Sonata No. 2 with pianist, Brad Clark.

Here she is rehearsing the 2nd mvt with Brad last night.  

Great work Rachel and best of luck to you this weekend.  I am very proud of this achievement for you!

VIOLIN TALK with David Rapkievian

It’s time for this week’s “Violin Talk” installment!

Look at David’s answers to his own puzzlers for all of you Violin and Physics fans!

“The answer to the puzzlers posed several weeks ago requires a brief review. Keeping in mind that 1) The string tension remains about the same whether or not the bridge is raised or lowered. 2) The resultant downward force upon the bridge is dependent upon the angle the strings make over the bridge (usually about 155 degrees). 3) This means that if the bridge is lowered, the angle each string makes over is increased. ( e.g. approaches a straight line which is 180 degrees, in which case the downward resultant force on the bridge would approach_________?).

The answer is zero pounds of downward force on the bridge! (Think of the force on a arrow while the bow string is straight and before the bow is drawn!)

Raising the bridge increases the downward force upon the bridge. Here is puzzler #2: If the string tension totals 50 pounds when the violin is tuned to A=440 with a 326mm string length, and ignoring some major playing issues, when the string angle approaches 0 degrees, 1) How high would the bridge be? and 2) What would the downward force upon the bridge measure in pounds?

The answer to bridge height is limited by the string length which was given as 326 mm. This means that as the string angle approaches zero degrees, the bridge approaches 326 mm high. ( note my caveat given in the original puzzler: “ ignoring some major playing issues….!!!.”) The second part of the question requires a wee bit of thought: The string tension is a constant 50 pounds at a 326 mm string length. This means for example that if you were to put a force meter attached to all the strings at the peg box end you would measure 50 pounds when the strings were in tune. BUT think about the force behind the bridge! The string tension if measured at the tailpiece side is ALSO 50 pounds! So if the string angle is brought to zero, the resultant downward force on the (326 mm) bridge is 50 lbs on one side of the bridge+50 lbs on the other side= 100 pounds total of downward resultant bridge force! Cool huh!?”

Thanks David!  You have really challenged us with this one and some of us just ran to go find our old Physics books!