Question

An object displaced from 5m height reaches ground at a distance of 10m.what is its final velocity?

Answer 1

For horizontal projectile motion the distance

$$d=v_0\sqrt{\frac{2h}{g}}$$

So, the initial velocity

 

$$v_0=d\sqrt{\frac{g}{2h}}=10\sqrt{\frac{10}{2\times 5}}=10\:\rm{m/s}$$