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Solution
Data:
Initial speed, Vi = 4.8 x 106 m/s
Charge of the proton, q = 1.6 x 10-19 C
Mass of the proton, m = 1.67 x 10-27 kg
Solution:
PART (a)
Distance, s = 0.034 m
Final speed, Vf = 0 m/s
Acceleration, a = F / m
= q E / m
= (1.6 x 10-19)E / (1.67 x 10-27)
= 9.58 x 107 E
From the equations of motion,
Vf2 - Vi2 = 2as
0 - (4.8 x 106 )2 = 2(9.58 x 107 E )(0.034)
So, E = - 3.537 x 106 N/C
Magnitude of electric field E = 3.537 x 106 N/C
Direction: Horizontally towards left
PART (b)
The angle counterclockwise from left is zero.
PART (c)
Acceleration, a = q E / m
= (1.6 x 10-19)(-3.537 x 106) / (1.67 x 10-27)
= - 3.388 x 1014 m/s2
From the equation of motion,
Vf = Vi + at
0 = 4.8 x 106 + ( - 3.388 x 1014 ) * t
Time, t = 1.42 x 10-8 s
PART (d)
Mass of electron, m = 9.1 x 10-31 kg
Charge of electron, q = 1.6 x 10-19 C
Distance, s = 0.034 m
Final speed, Vf = 0 m/s
Acceleration, a = F / m
= q E / m
= (1.6 x 10-19) E / (9.1 x 10-31)
= (1.76 x 1011) E
From the equations of motion,
Vf2 - Vi2 = 2as
0 - (4.8 x 106)2 = 2 (1.76 x 1011 E)(0.034)
So, E = - 1925.13 N/C
Magnitude of electric field = 1925.13 N/C
Direction: Horizontally towards the right

