Answer: I think, the number of oscillations in a given period of time.
Explanation: Well I guess because in a period time is known as the rate of occurrence of the wave. Hope this helps!
 
        
                    
             
        
        
        
Answer:
Explanation:
Lattice energy is the energy required to separate one mole of an ionic solid compound into its components gaseous cations and anions.
Due to increase in size of the ions, the lattice energy decreases while the lattice energy increases as the charge of the ions increases.
When the size increase, the distance between the nuclei also increase leading a decrease the force of attraction between the nuclei
 
        
             
        
        
        
Choices 'a', 'c', and 'd' are true.
In choice 'b', I'm not sure what it means when it says that masses 
are 'balanced'.  To me, masses are only balanced when they're on
a see-saw, or on opposite ends of a rope that goes over a pulley.
Maybe the statement means that the mass of the nucleus and the 
mass of the electron cloud are equal.  This is way false.  It takes 
more than 1,800 electrons to make the mass of ONE proton or 
neutron, and the most complex atom in nature only has 92 electrons 
in it.  So there's no way that the masses of the nucleus and the electrons
in one atom could ever be anywhere near equal.
        
             
        
        
        
Answer:
So the minimum force is
32.2Newton
Explanation:
To solve for the minimum force, let us assume it to be F (N)
So 
F=mgsinA
But 
=>>>> coefficient of static friction x (F + mgcosA
=>3 x 9.8 x sin35 = 0.3 x (F + 3 x 9.8 x cos35)
So making F subject of formula
F + 24.0 = 56.2
F = 32.2N
 
        
             
        
        
        
 Contact forces is the answer