A particle with charge $+4\mathrm{.}20$ nC

is in a uniform electric field E$$

directed to the left. The charge is released from rest and moves to the left; after it has moved $6\mathrm{.}00$ cm

$,$ its kinetic energy is $+2\mathrm{.}20$

$106$

J

$.$ What is the work done by the electric force? What is the potential of the starting point with respect to the end point? What is the magnitude of E$$

$?$