The tension in the string between the boxes is the same on either side of each box because the surface is frictionless, so T1=T2=T3=F.
let's consider the three boxes individually.
If they are connected by a string, and the string is being pulled by a force F, the tension in the string will vary along its length.
Let's label the boxes as A, B, and C from left to right. The force F is applied to box A.
The tension in the string is denoted as T1, T2, and T3 between boxes A and B, B and C, and C and the external force F, respectively.
The tension in the string is transmitted through each box. Since the surface is frictionless, the tension in the string is the same on either side of each box.
Now, let's analyze the forces acting on each box:
- Box A:
- Tension T1 acts to the right.
- External force F acts to the right.
- There are no other horizontal forces.
- Net force on box A is F, so T1 = F.
- Box B:
- Tension T1 acts to the left.
- Tension T2 acts to the right.
- There are no other horizontal forces.
- Net force on box B is zero, so T1 = T2.
- Box C:
- Tension T2 acts to the left.
- Tension T3 acts to the right.
- There are no other horizontal forces.
- Net force on box C is zero, so T2 = T3.
Considering all the boxes together:
- T1 = F (from box A).
- T1 = T2 (from box B).
- T2 = T3 (from box C).
So, T1 = T2 = T3 = F.
Therefore, the correct answer is 1) T1 = T2 = F.