Answer:
a
Explanation:
what the heck is a medium
Sunshine will help prode vitamin C
To solve this problem we will apply the concepts related to wavelength as the rate of change of the speed of the wave over the frequency. Mathematically this is

Here,
v = Wave velocity
f = Frequency,
Replacing with our values we have that,

\lambda = 0.68m
The distance to move one speaker is half this

Therefore the minimum distance will be 0.34m
Answer:
A first-class lever: fulcrum is between input and output force; second-class lever: output force is between input force and fulcrum; third-class lever: input force is between fulcrum and output force