placed so that the force on +q can cancel out?

Beams of high-speed protons can be produced in "guns" using electric fields to accelerate the protons. (a) What acceleration would a proton experience if the gun's electric field were 2.01 × 104 N/C? (b) What speed would the proton attain if the field accelerated the proton through a distance of 0.991 cm?

A proton and an alpha particle (charge = 2e, mass = 6.64 ✕ 10−27 kg) are initially at rest, separated by 8.76 ✕ 10−15 m. (c) Find the speeds of the proton and alpha particle, respectively, at infinity

A single proton is accelerated in a uniform E-field (directed eastward) at 3.2x10^8 m/s^2. Find the magnitude of the field and direction of the acceleration.