ans: B
Kinetic energy = 
= 
= 50J
ps. the height will only affect its potential energy, not kinetic.
 
        
             
        
        
        
Investigators are most likely to use the case history method when they study <span>a rare behavior or an unusual person.
They do this to obtain some sort of basis that they could use as a pointer to make their decision regarding the similar case (after figuring out the difference in situation between each period)</span>
        
             
        
        
        
Answer:
The magnitude of the second charge is  or
 or 
Explanation:
The work done in bringing a charged particle from one point to another in the presence of some electric field is equal to the change in the electric potential energy of the charge in moving from one point to another.
The electric potential energy of some charge  at a point in the electric field of another charge
 at a point in the electric field of another charge  is given by the product of the amount of charge
 is given by the product of the amount of charge  and electric potential at that point due to the charge
 and electric potential at that point due to the charge  .
.

The electric potential at that point is given by

where  is the Coulomb's constant.
 is the Coulomb's constant.
Therefore, 

Now, We have given two charges  and
 and  , whose value is to be found.
, whose value is to be found.
When the two charges are infinitely dar apart, the electric potential energy of the system is given by

When the coordinates of position of the two charges are

The distance between the two charges is given by

The electric potential energy of the charges in this configuration is given by

The change in the electric potential energy of the system is equal to the work done to bring the system from inifinitely far apart position to given configuration.
Therefore, 
