7

Horizontal component of tension (Eq. ) -

The horizontal component of the tension remains constant across the entire string. The reason for this is that if the x-components of the tension were not constant, then some segments of the string would feel more tension on one side than on the other and this would cause them to move in the x-direction. As the segments of the string do not move in the x-direction, we conclude that the x-component of the tension must be constant throughout.