18.5-0.5= 18
18/3= 6
So r=6
1 light-year = roughly 5,874,601,700,000 miles. (rounded)
To work it out, take the speed of light, and change units a few times:
(186,282.397 miles/second)
times
(86,400 second/day)
times
(365 day/year)
= (186,282.397 x 86,400 x 365) mile/year .
You can whip that out on your calculator in no time.
This is the answer check it out
To answer the problem we would be using the formula:v=λ*f
where v=343 m/s
length of standing wave
λ=2*L=1.6m (since both of the ends are open),
L=80.0cm =0.8m; but we are going to rearrange it.
Therefore fundamental frequency is:
f=v/λ
= 343/(2*0.8)
=214.375 Hz
