strain is a physical property, when material undergoes deformation within elastic limit, under static loading ,for eg in 1D strain,the factor ∆L/L is uniformly distributed along the length for each smaller length..still scrathing ur head..ok
Take a ruler 20 cm =L, apply a normal stress, such that it's new length becomes 30 cm, consider no width deformation , so if we will calculate the strain for this
For L cm length the deformation =10 cm (30–20)
So, for unit length deformation = 10/20=1/2
This is the strain for each unit length across the scale, 1/2 is a factor, which when multiplied by original length (20cm) gives the deformation value along length i.e 10cm
So it is a factor, but it remains constant for each unit length, because we assumed static loading, not dynamic loading, and within elastic limit…
According to Hooke's law ,stress is directly proportional to strain