This question is asked to gauge whether or not the interviewee is familiar with Euler-Bernoulli beam theory, which is typically covered in the first years of engineering school. A cantilevered beam refers to a structure that is fixed on one end and allowed to flex or bend on the other end, like a diving board at a swimming pool. You can calculate the deflection using the force applied (F), the length of the beam (L), the elastic modulus of the material (E), and the cross sectional area moment of inertia (I). The specific equation is (FL3)/(3EI).