A bird is sitting on the top of a vertical pole 20 m high and its elevation from a point O on the ground is 45∘. It flies off horizontally straight away from the point O. After one second, the elevation of the bird from O is reduced to 30∘. Then the speed (in m/s) of the bird is

A bird is sitting on the top of a vertical pole 20 m high and its elev

1.	A bird is sitting on the top of a vertical pole 20 m high and its elevation from a point O on the ground is 45∘. It flies off horizontally straight away from the point O. After one second, the elevation of the bird from O is reduced to 30∘. Then the speed (in m/s) of the bird is
Answer» A bird is sitting on the top of a vertical pole $20 m$ high and its elevation from a point $O$ on the ground is $45^{\circ}$ . It flies off horizontally straight away from the point $O$ . After one second, the elevation of the bird from $O$ is reduced to $30^{\circ}$ . Then the speed (in $m / s$ ) of the bird is