Answer:

Explanation:
 = Permittivity of free space =
 = Permittivity of free space = 
 = Surface charge density =
 = Surface charge density = 
 = 0.57-0.26
 = 0.57-0.26 
q = Charge = 
m = Mass of object = 
Electric field due to a sheet is given by

Electric field is given by

Voltage is given by

Kinetic energy is given by


The initial speed of the object is 
 
        
             
        
        
        
Answer:
  h = 20 m
Explanation:
given.
height, h = 10 m
Potential energy at 10 m = 50 J
Kinetic energy at 10 m = 50 J
maximum height the ball will reach, H = ?
Total energy of the system
 T E = 50 J + 50 J
 T E = 100 J
now, 
A h = 10 m
 P E = m g h
50 = m g x 10
mg = 5 ..............(1)
at the top most Point the only Potential energy will be acting on the body.
now, TE = Potential energy
  100 = m g h
 5 h = 100
  h = 20 m
hence, the maximum height reached by the ball is equal to 20 m.
 
        
             
        
        
        
Answer: 0 km/h
Explanation:
As a vector, the plane's velocity is 100 km/h (west) - 100 km/h (east)  = 0 km/m.
To an observer on the ground, the plane will be standing still.
        
             
        
        
        
Answer:
the angle of incident is 40°
Explanation:
NQ is the normal to the mirror, therefore
angle NQA =90°
PQA = 50°
incident angle = NQA - PQA
90°- 50° = 40°
note that the angle of reflection is equal to the angle of incident