A790n person runs up a flight of 40 stairs (.25m for each step) in 20 seconds, and then down 10 steps in 5 seconds. how much total mechanical work is completed? how much total mechanical power is generated? show all work.

Give an example of a collision in real life. use the law of conservation of energy to describe the transfer of momentum. be sure and discuss the momentum before and after the collision occurs. you will need at least 3 sentences to thoroughly answer this question