42. An alpha particle is a nucleus of helium. It has twice the charge and four times the mass of theproton. When they were very far away from each other, but headed toward directly each other, aproton and an alpha particle each had an initial speed of 0.0030c, where c is the speed of light. Whatis their distance of closest approach? (c = 3.00 x 108 m/s, ke = 1/4πε0 = 8.99 x 109 N ●m2/C2, e =1.60 x 10-19 C, mproton = 1.67 x 10-27kg)
(A) 2.1 x 10-13 m
(B) 3.3 x 10-13 m
(C) 2.6 x 10-13 m
(D) 2.9 x 10-13 m
(E) 4.2x 10-13 m.