Answer:
3.57 m/s
Explanation:
The sum of the 2 momentums Is equal the finale momentums. so if momentums Is q, v Is velocity and m Is Mass, q3=m1*v1+m2**v2=16+9=25 m*kg/s
q3=m3*v3
v3=q3/m3=25/(4+3)=3.57m/s
 
        
             
        
        
        
Friction occurs between two contacting surfaces. The coefficient of friction is very much dependent on the roughness of these surfaces. Some of the many ways in which the coefficient can be lessened or decreased are to lubricate the surface or make it shiny by eliminating the spikes which caused the roughness. 
        
             
        
        
        
The value of 'g' is not affected by rotation at any place on Earth.
        
             
        
        
        
Answer:
The answer is C.
Explanation:
I guessed and it was right
 
        
                    
             
        
        
        
Answer:
 ρ/ρ2 = 3 / R₀       the two densities are different
Explanation:
Density is defined as
        ρ = M / V
As the nucleus is spherical
        V = 4/3 π r³
Let's replace
       ρ = A / (4/3 π R₀³)
       ρ = ¾ A / π R₀³
b)
       ρ2 = F / area
The area of a sphere is
      A = 4π R₀²
      ρ2 = F / 4π R₀²
      ρ2 = F / 4π R₀²
Atomic number is the number of protons in the nucleon in not very heavy nuclei. This number is equal to the number of neutrons, but changes in heavier nuclei, there are more neutrons than protons.
Let's look for the relationship of the two densities
      ρ/ρ2 = ¾ A / π R₀³ / (F / 4π R₀²)
      ρ /ρ2 = 3 (A / F) (1 / R₀)
In this case it does not say that the nucleon number is A (F = A), the relationship is
      ρ/ρ2 = 3 / R₀
I see that the two densities are different