The correct answer for the question that is being presented above is this one: "a. only from an instructor or supervisor." Ideally, rewards should be given immediately and frequently but <span>only from an instructor or supervisor to show authority. </span>
        
             
        
        
        
F=ma
Force is 50N. Acceleration is 25 m/s^2.
50N=m*25 m/s^2
Divide both sides by 25.
mass=2 kg
        
             
        
        
        
Car is moving on the glassy slope with constant speed
Now we know that 

so acceleration is rate of change in velocity
as we know that velocity is constant here so acceleration is zero
so here 

now as we know by Newton's II law

since a = 0

so net force will be ZERO on it during this motion
 
        
             
        
        
        
The answer is A.number of protons in the nucleus.