Explanation:
In the given situation two forces are working. These are:
1) Electric force (acting in the downward direction) = qE
2) weight (acting in the downward direction) = mg
Therefore, work done by all the forces = change in kinetic energy
Hence,  
       
It is known that the weight of electron is far less compared to electric force. Therefore, we can neglect the weight  and the above equation will be as follows.
    
          v = 
            = 592999 m/s
Since, the electron is travelling downwards it means that it looses the potential energy. 
 
        
             
        
        
        
Answer:
Explanation:
b) Gravity reduces the initial upward velocity to zero in a time of
t = v/g = 40/10 = 4 s
a) h =  v₀t + ½gt² = 40(4) +  ½(-10)4² = 80 m
or
v² = u² + 2as
h = (0² - 40²) / 2(-10) = 80 m
 
        
             
        
        
        
Answer:
Startinfg speed is 13.82 m/s
Explanation:
Use equation for realtion between start and final speed :
Vf=Vs+a*t
Vf-final speed
Vs-start speed
Vf=24.44m/s
a=1.77m/s²(acceleration)
t=6.00s(Time)
Vf=Vs+a*t
Vs=a*t-Vf
Vs=1.77m/s²*6s-24.44m/s
Vs=-13.82m/s