Answer:
They can travel in a vacuum.
Explanation:
» Only electromagnetic waves travel through vacuum. The other mechanical waves require a material medium to travel.

 
        
                    
             
        
        
        
<span>The distance between wave crests is called wavelength. It is a characteristic shared by waves of all kinds, including ocean waves and sound waves. Wavelength is measured from the highest point, or summit, of one wave's crest to the summit of the next wave's <span>crest</span></span>
<span><span>hope this helps</span></span>
 
        
             
        
        
        
Answer
given,
mass of satellite = 545 Kg
R = 6.4 x 10⁶ m
H = 2 x 6.4 x 10⁶ m
Mass of earth = 5.972 x 10²⁴ Kg
height above earth is equal to earth's mean radius 
a) satellite's orbital velocity
    centripetal force acting on satellite = 
      gravitational force = 
     equating both the above equation
     
       
       
           v = 5578.5 m/s
b) 
    
    
           T = 14416.92 s
           
           T = 4 hr
c) gravitational force acting 
   
   
       F = 5202 N
 
        
             
        
        
        
Is there any types of answer to get an idea