Physics 19 Mechanical Waves (4 of 21) Finding the Tension on a String

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In this video I will show you how to calculate the tension of a (single harmonic) 0.6m string (one harmonic of a wave triain).

[@pamelajumbo4627]

Sir, you are the best at explaining physics in a comprehensive and understandable manner. Thank you for posting these helpful videos!

[@MichelvanBiezen]

Pam, Thank you for the note. It is good to know that students around the world are being helped by these videos.

[@Worldmemes4]

I find your online vedeos improving my grades...thank you sir..

[@MichelvanBiezen]

Glad to hear that

[@Worldmemes4]

Understanding 3hrs lecture in 10mins.... exciting.. interesting...

[@MichelvanBiezen]

Glad it helped.

[@gdilis6164]

i wish you were my physics prof, great job

[@curtpiazza1688]

440 Hz......on an 88 key piano that's the frequency of the note "A" above middle- "C" ! 😊 Thanx! ❤

[@MichelvanBiezen]

Good input. 🙂

[@thomasmerrill7470]

In a standing wave, will the wavelength always be = 2L? Or can there be multiple nodes, making the wavelength = 2 x The length of one node?

[@MichelvanBiezen]

Thomas, The wavelength will be equal to 2L ONLY in the fundamental frequency. For higher harmonics the wavelength will be shorter according to the number of nodes on the string.

[@mihaly1027]

Could you have a problem such as this one where tension force could cause a torque on a pulley? Would it be possible? Just curious

[@nellvincervantes3223]

Sir how do you calculate the force on the vibration cord to shorten it to a desired wavelength?

[@MichelvanBiezen]

First you find the v from the desired wavelength: v = f x wavelength Then you find the force v = sqrt (T / (m/L))

[@haeeun625]

like Thomas Merrill asked, will the wavelength always be 2L in a standing wave?

[@MichelvanBiezen]

Haeeun, Only if the string is vibrating in the fundamental frequency. Since the tension determines the velocity of the wave on the string, the velocity must be constant. Therefore the wavelength depends on the vibrational frequency, or better said, the frequency depends on the wavelength. So, how do we changed the wavelength? By plucking the string at a different location (like on a guitar, or a violin) If you pull the string at the center, that will cause vibrations at the fundamental frequency. If you pull the string at a distance 1/4 the length of the string, the frequency will be twice the fundamental frequency and the wavelength will be equal to the length of the string.

[@huejass9130]

how do u find tension with only frequency and mass

[@sashabagdasarow497]

You need length too.

[@drrobotnik5376]

Never seen newtons get combined with wavelength before.

[@alfredchen4579]

Thanks sir, it was really helpful

[@pokerdotify]

I get the Tension as 446.05 N.

[@ThilebanTheEngineer]

you didn't divide it by 0.6. :)