At 4 m/s?
How do the two kinetic energies compare to one another? QUADRUPLES !
#3 What is the kinetic energy of a 2,000 kg bus that is moving at 30 m/s?
Potential energy
        
                    
             
        
        
        
B strength training I think that’s the answer
        
                    
             
        
        
        
Answer:
1) The greatest height attained by the ball equals 20.387 meters.
2) The time it takes for the ball to reach 15 meters approximately equals 1 second.
Explanation:
The greatest height will be attained when the ball stop's in the air and starts falling back to the earth.
thus using third equation of kinematics we obtain the height attained as 

where
'v' is the final speed of the ball
'u' is the initial speed of the ball
'a' is the acceleration that the ball is under which in this case equals 9.81 
's' is the distance it covers
Thus for maximum height applying the values in the equation we get

Using the same equation we can find the speed of the ball when it reaches 15 meters of height as  

the time it takes to reduce the velocity to this value can be found by first equation of kinematics as 

 
        
             
        
        
        
In reality we don't see the galaxy we see it's reflection .. the light hits or got emitted by the star travel all the way long to hit our eyes .. we see their reflection . everything around you that you see is it's reflection
        
             
        
        
        
Answer:
The mass number 204 – 82 protons = 122 neutrons
Explanation:
Hope this helps!