As the ball is moving in air as well as we have to neglect the friction force on it
So we can say that ball is having only one force on it that is gravitational force
So the force on the ball must have to be represented by gravitational force and that must be vertically downwards
So the correct FBD will contain only one force and that force must be vertically downwards
So here correct answer must be
<em>Diagram A shows a box with a downward arrow. </em>
 
        
             
        
        
        
Answer:
B. Maximum velocity of ejected electrons.
Explanation:
The ejection of electrons form a metal surface when the metal surface is exposed to a monochromatic electromagnetic wave of sufficiently short wavelength or higher frequency (or equivalently, above a threshold frequency),  which leads to the enough energy of the wave to incident and get absorbed to the exposed surface emits electrons. This phenomenon is known as the photoelectric effect or photo-emission.
The minimum amount of energy required by a metal surface to eject an electron from its surface is called work function of metal surface.
The electrons thus emitted are called photo-electrons.
The current produced as a result is called photo electricity.
Energy of photon is given by:

where:
h = Planck's constant
 frequency of the incident radiation.
 frequency of the incident radiation.
 
        
             
        
        
        
Well a basic explanation is that some elements have enough electrons to be considered stable. These elements do not need to react with other elements to gain more electrons. Reactive elements are no where near stable; they respond with other elements in order to become stable. The more unstable, the harsher the reaction is.
 
        
             
        
        
        
Answer:
Fossil fuels store energy from the sun as
 
        
                    
             
        
        
        
Answer:
10 m/s
Explanation:
The problem can be solved by using the law of conservation of momentum: the initial momentum has to be equal to the final momentum, so we can write the following


where
 is the mass of the first car
 is the mass of the first car
 is the initial velocity of the first car
 is the initial velocity of the first car
 is the mass of the second car
 is the mass of the second car
 is the initial velocity of the second car
 is the initial velocity of the second car
 is the final velocity of the two combined cars after the collision
 is the final velocity of the two combined cars after the collision
Re-arranging the equation and substituting the numbers, we find
