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Question

In Rutherford's famous scattering experiments that led to the planetary model of the atom, alpha particles (having charges of +2e and masses of 6.64 10-27 kg) were fired toward a gold nucleus with charge +79e. An alpha particle, initially very far from the gold nucleus, is fired at 1.0 107 m/s directly toward the nucleus, as in Figure P16.19. How close does the alpha particle get to the gold nucleus before turning around? Assume the gold nucleus remains stationary.

Answer 1

It is explained at http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/rutsca2.html#c5
To "turn around" the scattering angle is 180 degrees