A train passes by a pole with uniform acceleration ‘a’. Its front end when passes by it has speed ‘u’ and its back end when passes by it has speed ‘v’. Find speed of the middle part when it passes by the pole?

(1) $\sqrt{v^2+u^2}\over2$

(2) $\sqrt{v^2+u^2\over2}$

(3) $\sqrt{v^2-u^2\over2}$

(4) $\sqrt{v^2-u^2}\over2$

(1) $\sqrt{v^2+u^2}\over2$

(2) $\sqrt{v^2+u^2\over2}$

(3) $\sqrt{v^2-u^2\over2}$

(4) $\sqrt{v^2-u^2}\over2$