Tarzan is in trouble once again and Jane and Cheetah have to decide whether to try to bail him out. Jane and Cheetah (70kg combined) are perched on a cliff 10m above Tarzan (70kg) and can swing down on a vine and grab him. To get to safety, they need to get to a perch 5m above Tarzan on the other side. Determine the speed of Jane and Cheetah just before they would grab Tarzan. Assume no air drag or friction.