Answer:
Echolocation
Explanation:
.....................................
Yes because something that has been electrically charged can make other things move without touching them ( this is called force without contact)
Hoped this helped :)
A) heterogeneous mixture & I believe B?
I know A is correct though
Answer:
5541Hz
Explanation:
If the frequency of a wave is directly proportional to the velocity we have;
F = kV where;
F is the frequency
K is the constant of proportionality
V is the velocity
Since f = kV
K = f/v
K = F1/V1 = F2/V2
Given f1 = 412Hz v1 = 25.8m/s f2 = ? V2 = 347m/s
Substituting in the formula we have;
412/25.8=f2/347
Cross multiplying
25.8f2 = 412×347
F2 = 412×347/25.8
F2 = 5541Hz
The frequency heard will be 5541Hz
Answer:
1) f= 8.6 GHz
2) t= 0.2 ms
Explanation:
1)
- Since microwaves are electromagnetic waves, they move at the same speed as the light in vacuum, i.e. 3*10⁸ m/s.
- There exists a fixed relationship between the frequency (f) , the wavelength (λ) and the propagation speed in any wave, as follows:
![v = \lambda * f (1)](https://tex.z-dn.net/?f=v%20%3D%20%5Clambda%20%2A%20f%20%281%29)
- Replacing by the givens, and solving for f, we get:
![f =\frac{c}{\lambda} =\frac{3e8m/s}{0.035m} = 8.57e9 Hz (2)](https://tex.z-dn.net/?f=f%20%3D%5Cfrac%7Bc%7D%7B%5Clambda%7D%20%3D%5Cfrac%7B3e8m%2Fs%7D%7B0.035m%7D%20%3D%208.57e9%20Hz%20%282%29)
⇒ f = 8.6 Ghz (with two significative figures)
2)
- Assuming that the microwaves travel at a constant speed in a straight line (behaving like rays) , we can apply the definition of average velocity, as follows:
where v= c= speed of light in vacuum = 3*10⁸ m/s
d= distance between mountaintops = 52 km = 52*10³ m
![t = \frac{d}{c} = \frac{52e3m}{3e8m/s} = 17.3e-5 sec = 0.173e-3 sec = 0.173 ms (4)](https://tex.z-dn.net/?f=t%20%3D%20%5Cfrac%7Bd%7D%7Bc%7D%20%3D%20%5Cfrac%7B52e3m%7D%7B3e8m%2Fs%7D%20%3D%2017.3e-5%20sec%20%3D%200.173e-3%20sec%20%3D%200.173%20ms%20%284%29)
⇒ t = 0.2 ms (with two significative figures)