Three blocks of mass M1, M2 & M3 are connected by massless strings as shown on a frictionless table. Where T1 is the tension in the string between block M1 and M2, T2 is the tension in the string between block M2 and M3. They're pulled with a force F=40N. If M1=10 kg, M2= 6 kg and M3 = 4 kg, then tension T2 will be: