contestada

A tuning fork labeled 392 Hz has the tip of each of its two prongsvibrating with an amplitude of 0.600mma) What is the maximum speed of the tip of a prong?b) A housefly (musca domestica) with mass 0.0270 g isholding on to the tip of one of the prongs. As the prong vibrates,what is the fly's maximum kinetic energy? Assume that the fly'smass has a negligible effect on the frequency of oscillation?

Respuesta :

a) 1.48 m/s

The tuning fork is moving by simple harmonic motion: so, the maximum speed of the tip of the prong is related to the frequency and the amplitude by

[tex]v_{max}=\omega A[/tex]

where

[tex]v_{max}[/tex] is the maximum speed

[tex]\omega[/tex] is the angular frequency

A is the amplitude

For the tuning fork in the problem, we have

[tex]\omega=2\pi f=2 \pi(392 Hz)=2462 rad/s[/tex], where f is the frequency

[tex]A=0.600 mm=6\cdot 10^{-4} m[/tex] is the amplitude

Therefore, the maximum speed is

[tex]v_{max}=(2462 rad/s)(6\cdot 10^{-4}m)=1.48 m/s[/tex]

b)  [tex]3.0\cdot 10^{-5} J[/tex]

The fly's maximum kinetic energy is given by

[tex]K=\frac{1}{2}mv_{max}^2[/tex]

where

[tex]m=0.0270 g=2.7\cdot 10^{-5} kg[/tex] is the mass of the fly

[tex]v_{max}=1.48 m/s[/tex] is the maximum speed

Substituting into the equation, we find

[tex]K=\frac{1}{2}(2.7\cdot 10^{-5}kg)(1.48 m/s)^2=3.0\cdot 10^{-5} J[/tex]