1pt Calculate a numeric value for the electric field at the

1pt] Calculate a numeric value for the electric field at the point x = 4 m in diagram A.

Correct, computer gets: -5.0E-01 V/m

20. [1pt]
Calculate the force on a positive charge of 1 µC located at the point x = 4 m in diagram A. (If the force is parallel to the ?x axis, then the force is negative.)

Correct, computer gets: -5.0E-07 N

21. [1pt] Calculate the initial acceleration of a proton placed at the point
x = 4 m in diagram A. (If the acceleration is parallel to the ?x axis, then the acceleration is negative.)

Answer:  Last Answer: -2.87*10^38 m/s^2

I can\'t figure out 21. Please help. Thank you.

Solution

the acceleration is calculated as follows:

E = - dV/dx

F/q = - dV/dx

ma / q = - dV/dx

thus the acceleration:

a = -[dV/dx][q/m]

= - [(4-3)/(5-3)][1.6x10^-19 / 1.67x10^-27]

= - 4.79e+7 m/s^2