Suppose two cases where masses are attached to massless, inextensible strings.
In the first case a body which has a weight of 20 Newtons(downwards) is attached to a string which is acted upon by a force of 100 Newtons upwards.
In the second case, a body of weight 10 Newtons is attached to a string and again a force of 100 Newtons upwards is applied on the string.
These two cases are identical except for the magnitudes of the weights attached to the strings. However, I think that the tension in both strings will equal 100 Newtons(the reaction force for the upward force).
If this is correct, how is it that the string has the same tension when different forces are applied on it? Intuitively, shouldn't the string stretch more and have more tension when a larger force acts on it on one side.
And if the tension in both cases is not equal then how can the tension in the strings be calculated?