Question

A 51-kg vampire and 139-kg werewolf clash during the Feat of Strength part of the annual celebration of Festivus. The werewolf velocity just before the clash is 6 m/s and is directed upwards, while the vampire velocity at the moment of the collision is 10m/s and is directed down. They clash in mid-air exactly 11 meters above the ground. Vampire will starts feeding on werewolf at the moment of collision, and will not stop until they hit the ground. Find how long (in s) will the vampire feast on the werwolf? Calculate the answer to two decimal places