A proton accelerates from rest in a uniform electric field of 640. N/C. At some later time, its speed is 1.20×106 m/s. Find the magnitude of the acceleration of the proton.
a) 3.84 × 10⁶ m/s²
b) 4.80 × 10⁵ m/s²
c) 8.00 × 10⁵ m/s²
d) 6.00 × 10⁶ m/s²