- #1

These are some questions from my last assignment for the semester- I figured I would finish it all up before I head off the competitions for the next month. Again- I feel fairly confident with my answers- but I have had so much trouble in physics that I sometimes second-guess my work. Any help and/or comments would be great!

**1) True or False. The period of a body in simple harmonic motion is independent of its mass.**

True

**2) True or False. At resonance, very little energy is required to obtain a larger amplitude.**

True

***How exactly can you tell the difference (from drawings) as to whther or not they show complete of partial constructive/destructive interference? How do the direction of the forces make a difference?***

**3) The air temperature is 10* C. What is the wavelength of a sound emitted by a tuning fork having a frequency of 440 Hz?**

Using the equation V= (wavelegth)(frequency) as my base I first decided to find the frequency. To do this I used 331+.6(10) which is 337 m/s. I then substituted this into the equation and solved as follows: 337= w (440)

337/440= .765 m

is this correct?

**4) The wavelength of a wave generated by an AM broadcasting station is 405 m. In KHz, what is the frequency of the wave?**

Using 331 as the base velocity I used 331= 405 f

331/405=.817= 817 KHz

I think this sounds about right...

**5) A sound pulse is directed from one airplane to another that is 1255 m away. A reflected pulse is detected 8 seconds after the original pulse was transmitted. What is the temperature of the air surrounding the plane?**

V=d/t...d= 1255(2)=2510m

t= 8 s

V= 2510/8= 313.75

I then use 331 + .6x= 313.75 to find the temperature.

The resulting answer is -28.75 * C...is this right?

**6) A Wave having a frequency of 2 Hz is generated along a spring. The wave has a wavelength of .457 m. What is the speed of the wave along this spring?**

Here I am presuming "speed" to mean velocity. V= 2(.457)= .91 m/s

Does this sound correct?

**7) /a sonar signal of frequency 1005 Hz has a wavelength of 145 cm in water, What is the velocity in water?**

Again I use the equation V= Wavelength(F)

145 cm= 1.45 m so V= (1005)(1.45)

The answer is 1.46 x 10^3 m/s; correct?

Thank you so much for your time!