In 1911 Rutherford discovered the nucleus of an atom by observing the scattering of helium nuclei from gold nuclei. If a heliumnucleus with a mass of 6.68 x 10-27 kg, a charge of +2e,and an initial velocity of 1.50 x 107 m/s is projectedhead-on towards a gold nucleus with a charge of +79e, how closewill the helium atom come to the gold nucleus before it stops andturns around?
(Assume the gold nucleus is held in place by other gold atomsand does not move).