Help me for Physics, please?

Physics Question. Big Test tomorrow please help.?

• I have a big physics question tomorrow. And I really need some help. I tried doing the questions but i couldn't seem to find the right answers. Please If you could do them all please do them. But Its okay if you do just a couple or one. But I would really appreciate if you did them all. Please explain it to me too I dont wanna flunk physics its just too freakin hard heeeeeeelp. I can't seem to find the right formula to use A 755 N diver drops from a board 10. 0 m above the water's surface.Find the dvier's speed 5 m above the water's surface. Then find the diver's speed just before striking the water. An Olympic runner leaps over a hurdle. If the runner's initial vertical speed is 2.2m/s how much will the runner's center of mass be raised during the jump? A pendulum bob is released from some initial height such that the speed of the bob at the bottom of the swing is 1.9m/s. What is the initial height of the bob? And please put some explanation to make me understand.

• Answer:

  Hmm Well. 1) Use Galileo 2nd eq: v²=u²-2gs take u=0 intial at rest; g=10(approx) v²=2(10)5 v=10m/s similarly do 2nd. 2) There is no change in Center of Mass in Vertical Direction until he jumps. During Leap you should provide height of hurdle. 3)This is the ques of conservation of energy mgh=½mv² take g=10 solve it for h. h=0.242m :)