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:
2N
Explanation:
subtract  rthe two forces to see which is greater
4-2=2
 
        
             
        
        
        
Answer:
60 cm 
Explanation:
We are given;
- Focal length of a concave mirror as  30.0 cm 
- Object distance is 15.0 cm 
We are required to determine the radius of curvature.
We need to know that the radius of a curvature is the radius of a circle from which the curved mirror is part.
We also need to know that the radius of curvature is twice the focal length of a curved mirror.
Therefore;
Radius of curvature = 2 × Focal length
Therefore;
Radius of curvature = 2 × 30 cm
                                  = 60 cm