A proton is projected in the positive x direction into a region of a uniform electric field

Question:

A proton is projected in the positive x direction into a region of a uniform electric field E = - 6.00 x 105i N/C at t = 0. The proton travels 7.00 cm before coming to rest.
Determine
(a) The acceleration of the proton,
(b) Its initial speed, and
(c) The time at which the proton comes to rest.