mkelly1992
Jan 14, 2013, 11:40 AM
1)A jetskier is moving at 8.2 m/s in the direction in which the waves on a lake are moving. Each time he passes over a crest, he feels a bump. The bumping frequency is 1.05 Hz, and the crests are separated by 5.8 m. What is the wave speed?
so here I used speed = frequency x wavelength, for frequency 1.05 Hz and wavelength 5.8 m and got 6.09 m/s, the computer said that was wrong so I tried doubling the frequency(thinking that if they only counted the upper crests id need to include the troughs), then got 12.20 m/s which was also wrong.
2)The mass of a string is 5.3 × 10-3 kg, and it is stretched so that the tension in it is 150 N. A transverse wave traveling on this string has a frequency of 290 Hz and a wavelength of 0.53 m. What is the length of the string?
Here I used speed= square root of ( tension/mass/length), I calculated speed first by speed = frequency 290 x wavelength .53 got 153.7, plugged that in and got 184.14 m as the string length which the computer said was wrong.
Can anyone see where I've gone wrong? I've tried messing around with the sig figures but maybe that's my error? Thanks
so here I used speed = frequency x wavelength, for frequency 1.05 Hz and wavelength 5.8 m and got 6.09 m/s, the computer said that was wrong so I tried doubling the frequency(thinking that if they only counted the upper crests id need to include the troughs), then got 12.20 m/s which was also wrong.
2)The mass of a string is 5.3 × 10-3 kg, and it is stretched so that the tension in it is 150 N. A transverse wave traveling on this string has a frequency of 290 Hz and a wavelength of 0.53 m. What is the length of the string?
Here I used speed= square root of ( tension/mass/length), I calculated speed first by speed = frequency 290 x wavelength .53 got 153.7, plugged that in and got 184.14 m as the string length which the computer said was wrong.
Can anyone see where I've gone wrong? I've tried messing around with the sig figures but maybe that's my error? Thanks