The horizontal surface on which the objects slide is frictionless. If F = 12 N, find the tension in string 1 and string 2? The tension between mas M and mass 2M is T2 (labeled just 2 in the diagram) and the tension between 2M and 3M is T1 (labeled just 1 in the diagram). You don’t really need a value for M, or if it makes it easier, you can simply use any value you want, say M = 2 kg. The first mass would then be 2 kg, the second one, 4 kg and the third one would be 6 kg.
If M = 2.2 kg