The change in velocity (v₂ - v₁) is 
                <em> (-20) / (the object's mass)</em>.
Call it a crazy hunch, but I can't shake the feeling that there was more 
to the question before the part you copied, that mentioned the object's 
mass, and its velocity before this force came along.
        
             
        
        
        
Answer:
ELASTIC collision
kinetic energy is conservate
Explanation:
As the ball bounces to the same height, it can be stated that the impact with the floor is ELASTIC.
As the floor does not move the conservation of the moment
             po = pf
             -mv1 = m v2
- v1 = v2
So the speed with which it descends is equal to the speed with which it rises
Therefore the kinetic energy of the ball before and after the collision is the same
 
        
             
        
        
        
Hello
The final light will be white. In fact, each color of the visible spectrum is an electromagnetic wave with its own specific frequency and wavelength. White, instead, does not have a specific frequency: it is the sum of all the different wavelengths of the visible spectrum. Therefore, when recombining the spectrum of the refracted light all the different frequencies recombine together, and their sum gives white light.
(edited)
        
             
        
        
        
The answer would be '<span>The plane of a Foucault pendulum appears to shift its orientation' because it is an experiment to demonstrate the rotation of the earth.
Hope this helps.</span>