Three identical blocks, fastened together by a string, are pulled across a frictionless surface by a constant force.

Compare the tension on string A to magnitude of applied force F.

consider this. The tension on each segement is the total mass the rope is pulling behind it (either three, two, one block) times acceleartion.

the all have the same tension

In order to compare the tension on string A to the magnitude of the applied force F, we need to consider the forces acting on the system.

When the blocks are pulled by the applied force F, they experience an equal and opposite force in the forward direction due to Newton's third law of motion. This force is transmitted through the string, resulting in tension in the string.

In this scenario, since the blocks are identical and fastened together, the tension in the string is the same throughout. Therefore, the tension on string A is equal to the tension on the other parts of the string.

So, the tension on string A is equal to the magnitude of the applied force F.

To compare the tension on string A to the magnitude of the applied force, we need to consider the equilibrium of forces acting on the system.

In this scenario, we have three identical blocks that are fastened together by a string. Let's label these blocks as Block 1, Block 2, and Block 3. The direction in which the force is applied is indicated by the arrow, which we'll call the applied force F.

Since the surface is assumed to be frictionless, there is no frictional force between the blocks and the surface. Therefore, the only external force acting on the system is the applied force F.

When the blocks are being pulled, each block will experience the same magnitude of force because they are identical and connected by a string. The tension in the string represents the force transmitted from one block to the next. So, string A will experience the same tension as string B and string C.

Now, let's analyze the equilibrium of forces acting on each block individually:

Block 1: The applied force F is acting on Block 1, and it is being balanced by the tension in string A, pulling it in the opposite direction. Therefore, the tension in string A is equal in magnitude but opposite in direction to the applied force F.

Block 2: Block 2 is being pulled by the tension in string A in one direction and by the tension in string B in the opposite direction. Since the blocks are identical, the tension in string B is equal in magnitude to the tension in string A. Thus, the tension in string B is also equal in magnitude but opposite in direction to the applied force F.

Block 3: Block 3 experiences the same forces as Block 2 but in the opposite direction. The applied force F pulls it in one direction, and the tension in string B pulls it in the opposite direction. Again, the tension in string B is equal in magnitude to the tension in string A, so the tension in string B is also equal in magnitude but opposite in direction to the applied force F.

In conclusion, the tensions in strings A and B are equal in magnitude and opposite in direction to the applied force F. Therefore, the tension on string A is equal to the magnitude of the applied force F.