Why is tension at a specific point in a string in 2 directions? For example in the first part of image 1, the string is pulling the two blocks upwards. And in the second part of image 1, the string is pulling the pulley down too. Does tension at a point in a string try to pull the point in 2 directions? And in image 2, why is the bottom most pulley (which is not hinged) pulled up by a tension 2T? If it is, that means there is no net force acting on it but then how is it moving down if there is no force on it? No force means no acceleration but still it can have a constant velocity (no acceleration) with which it moves down. But why and how does it get that velocity?