4.1.5: 9, 11, 13, 15, 17
4.2.5: 17, 19
4.3.5: 11, 17, 19, 25 (just find the mass)
5.1.1: 1, 3, 11, 15
5.2.1: 7, 9, 13, 17 (just find the mass), 19, 21
5.3.1: 5, 11, 13, 15, 17 (just find the mass)

Questions from Tuesday's problem sheet