Giancoli Ch. 30 – p. 860, Problems #37, 39, 40, 42, 55, 59, 61, 66, 67a, 69

37a) 1.5 x 10^-10 y

37b) 2.3 h

39) 0.0625

40) 0.015625

42) 7 α particles; 4 β^– particles

55) thorium-232 -> radium-228 -> actinium-228 -> thorium-228 -> radium-224 -> radon-220; uranium-235 -> thorium-231 -> protactinium-231 -> actinium-227 -> thorium-227 -> radium-223

59) 2.3 x 10⁴ y

61) 41 y

66) 193 y

67a) iridium-191

69) 550 MeV; 2.5 x 10¹² J