Two protons are released from rest at a separation distance of approximately one atomic diameter, equal to 1.0 × 10^-10 m, from each other in vacuum space. Find the magnitude of their initial acceleration. [Hint: A proton has mass m_p = 1.67 × 10^-27 kg, charge = 1.60×10^-19 C, and The Coulomb's constant k = 8.99 × 10⁹ N⋅m²/C².]