Answer:
A. Longer wavelengths and less dangers
Explanation:
Radio waves are at the lowest end of the EM spectrum, they have the longest wavelength of any other EM waves, the lowest energy and, accordingly, the lowest frequency;
Their low energy and frequency means they pose little risk of harm or danger as they don't get absorbed by human being.
 
        
             
        
        
        
Answer: The answer is 333.3333 repeating
Explanation:
Divide the mass by the volume. 
 
        
                    
             
        
        
        
(a) The lowest frequency (called fundamental frequency) of a wire stretched under a tension T is given by

where
L is the wire length
T is the tension
m is the wire mass
In our problem, L=10.9 m, m=55.8 g=0.0558 kg and T=253 N, therefore the fundamental frequency of the wire is

b) The frequency of the nth-harmonic for a standing wave in a wire is given by

where n is the order of the harmonic and f1 is the fundamental frequency. If we use n=2, we find the second lowest frequency of the wire:

c) Similarly, the third lowest frequency (third harmonic) is given by
 
 
        
        
        
<span>By adding "south", the speed had both magnitude AND direction, becoming a vector, not a scalar which generic "speed" is. So the second option can be eliminated. Let's analyze the other part(s). A velocity is a distance/time. Do we have that? Yes! -> miles/hour. So, velocity is an option that theoretically fits this question. Buttt... It gives us a time, and acceleration is a change in a velocity (speed, with a direction)/time. So because it says "after 10 minutes", we consider the big picture to be talking about the change in velocity during that time span, which is simplified as "the acceleration" over that time. :)</span>
        
                    
             
        
        
        
Answer:
The work done by the crane is, W = 441000 J
The power of the crane is, p = 3675 watts
Explanation:
Given data,
The mass of the object, m = 900 kg
The object is lifted to the height, h = 50 m
The time taken to lift the mass, t = 2 min
                                                       = 120 s
The work done by the crane on the object is equal to the potential energy of the object at that height. It is given by the formula,
                                     W = P.E = mgh joules
Substituting the values in the above equation
                                      W = 900 kg x 9.8 m/s² x 50 m
                                          = 441000 J
The work done by the crane is, W = 441000 J
The power of the crane,
                                   P = W / t
                                      = 441000 J / 120 s
                                      = 3675 watts
Hence, the power of the crane is, p = 3675 watts