A hunter is riding an elephant of height `4 m` moving in straight line with uniform speed of `2m//sec`. A deer running with a speed `V` in front at a distance of `4sqrt(5)` moving perpendicular to the direction of motion of the elephant. If hunter can throw his spear with a speed of `10m//sec`. relative to the elephant, then at what angle `theta` to it's direction of motion must he throw his spear horizontally for a successful hit. Find also the speed 'V' of the deer.

Answer

`[37^(@), 6m//s]`