An elastic string of length is stretched through a length e by a force f the area of cross section of the spring is A and its young modulous is E. declore the expression between f,e,E,l
The expression for the force required to stretch the elastic string through a length e can be given by Hooke's law, which states that the force required to stretch or compress a spring is directly proportional to the distance it is stretched or compressed, as long as the limit of proportionality is not exceeded. Mathematically,
F = k x e
where F is the force applied, e is the extension or compression of the spring, and k is the spring constant. The spring constant is a measure of the stiffness of the spring and can be expressed as k = E x A / l, where E is the Young's modulus of the material, A is the area of cross section of the spring, and l is the original length of the spring. Substituting this value of k in the above expression, we get
F = E x A / l x e
This gives us the expression for the force required to stretch the elastic string through a length e in terms of its Young's modulus E, the area of cross section A, and the original length of the spring l.