Explanation:
the answers are the first 3.
 
        
                    
             
        
        
        
Answer: 
we have formula of frequency :
frequency(f)= speed of sound(c)/wavelength(λ)
for wavelength we swipe it with frequency as follows
λ=c/f
λ=300,000,000/101,700,000
λ=2.949
 
        
             
        
        
        
Answer:
Using the given values
F = K q^2 / r^2 = 9 * 10E9 * (1.6 * E-19)^2 / (5.18 * E-15)^2 N
E = 9 * 1.6^2 / 5.18^2 * 10 = 8.5 N
 
        
             
        
        
        
<h2>
Answer: 540 J</h2>
Explanation:
The Work  done by a Force
 done by a Force  refers to the release of potential energy from a body that is moved by the application of that force to overcome a resistance along a path.
 refers to the release of potential energy from a body that is moved by the application of that force to overcome a resistance along a path.  
Now, when the applied force is constant and the direction of the force and the direction of the movement are parallel, the equation to calculate it is:  
 (1)
 (1)  
In this case both (the force and the distance in the path) are parallel (this means they are in the same direction), so the work  performed is the product of the force exerted to push the box
 performed is the product of the force exerted to push the box  by the distance traveled
 by the distance traveled  .
.
Hence:  
 (2)
   (2)
