We want a sound wave with a wavelength of 0.52 meters or a natural fraction thereof. We'll work in MKS.
w = 0.52/n
That's length. We have speed 344 meters/second so w corresponds to a frequency of
f = 344 / w = n (344/.52)
f = 661.5 n Hertz
I don't really agree with how they're saying it, but all the fundamental talk is probably trying to tell us n=1,
Answer: 661.5 Hertz
Any multiple of that will also produce constructive interference; we can go to about n=30 before we're out of the audio range.
<span>How much kinetic energy does a 7.2-kg dog need to make a vertical jump of 1.2 m?
</span>Answer:
85 Joule (approx)
Explanation:
Potential energy at highest point
<span><span>P.E = mgh = 7.2 kg × 9.8 m/s2</span>×1.2 m≈85 Joule</span>
I am not sure about this one
Answer: 1ST OPTION A car increases its speed from 5 m/s to 10 m/s
Explanation:IN 1ST OPTION : because the vel and force are in the same direction therefore acceleration is positive
IN 2ND & 3RD OPTION : the force and velocity in opposite direction so its velocity decreases therefore acceleration is negitive
