\({s_x} = {v_x}t = 3 \times 4 = 12\;m\)

Force along \(OF\) (perpendicular to \(OE\)) \(= 4\, N\)

\(\therefore {a_y} = \frac{F}{m} = \frac{4}{2} = 2\;m/{s^2}\)

Displacement of body in \(4\, sec\) along \(OF\)

\(⇒\) \({s_y} = {u_y}t + \frac{1}{2}{a_y}{t^2}\)\( = \frac{1}{2} \times 2 \times {(4)^2} = 16\;m\) [As \({u_y} = 0\)]

\(\therefore \) Net displacement \(s = \sqrt {s_x^2 + s_y^2} \; = \sqrt {{{(12)}^2} + {{(16)}^2}} = 20\;m\)