Alright I have a few problems here. 1). A bird is flying with a speed of 18 m/s over water when it accidentally drops a 2 kg fish. If the altitude of the bird is 5.40 meters and friction is disregarded, what is the speed of the fish when it hits the water? My work: I don't know if I did this one right so if you could check that would be great. I did PE= (2kg)(9.81m/s^2)(5.4m) = 106 PE So I made KE at the point of the water 106 KE and 0 PE (potential energy.) Then I did 106 = 1/2 * 2kg * v^2 I got it to equal v = 10.29 m/s is that correct? 2) A 755N Diver drops from a 10 m boarding above the waters surface. Find the divers speed 5 meters above the water. Then find the diver's speed just before it hits the water. ok here i got 9.9 m/s for the part 5 meters above water is that correct? and then I got 14 m/s when striking the water? (Part B) If the same diver leaves the board with initial upward speed of 2.0 m/s find the divers speed when striking the water. I worked it out until here now I dont know what to do next 3) An Olympic runner leaps over a hurdle. If the runners initial vertical speed is 2.2 m/s how much will the runners center mass be raised during the jump? Work: im not really sure what to do here but is the answer .5 meters up? I don't know if this is a correct equation, but I did V^2 = mgh 4) A pendulum bob is released from some initial height such that the speed of the bob at the bottom of the swing is 1.9 m/s. what is the initial height of the bob? Ok here i don't know what to do really. I think it goes along the lines of one above, but im not sure if that was right either.