(Structural eng.) The increase in length, I, in a rectangular slab of metal that’s fixed a...

(Structural eng.) The increase in length, I, in a rectangular slab of metal that’s fixed at one end and pulled by a force at its other end (see Figure) is given by this formula:

I = (F × l) / (w × d × ε)

I is the increase in length (m, mm, ft, in).

F is the applied force (N, lbf).

l is the bar’s initial length (m, mm, ft, in).

w is the bar’s width (m, mm, ft, in).

d is the bar’s depth (m, mm, ft, in).

ε is the metal’s elasticity modulus. 

Figure: A suspended slab of metal

Using the formula, determine the units for the elasticity modulus.