plz help be first to help and show work to get 5 stars and chose to have the best answer!?

Question

1.a 90kg rock climber first climbs 45m upward to the top edge of a quarry, then, from the top, descends 85m to the bottom. find the potential energy of the climber at the edge and at the bottom, using the initial height as the reference level.

2. a 50kg shell is shot from a cannon at earth's surface to a height of 4 times 10 to the 2nd power.
a) what is the gravitational potetial evergy with respect to earth's surface of the earth-shell system when the shell is at this height?
b)what is the change in potential energy of the system when the shell falls to a height of 2 times 10 to the 2nd power meter?

3)a person weighing 630N climbs up a ladder to a height of 5m.
a)what work does the person do?
b)what is the increase in the gravitational potential evergy of the person from the ground to this height?
c) where does the energy come from to cause this increase in the gravitational potential energy?


BE THE FIRST TO FINISH ALL PROBLEMS AND SHOW WORK AND GET 5 STARS, BEST ANSW

Answer 1

These problems are not that difficult. I'm sure you have a book of some sort that would explain the concept to you.

Also, you're on the internet asking for help. Why not just take the time you used to type up all these questions and search google for some information.

http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch5/tempframe.html

That took me 2.48 seconds (says yahoo.com)

Answer 2

Im not doing the homework for you, but i will give you the equations as much as i remember them

Gravitational Potential Energy = Mass x Gravitational Field Strength* x Height
GPE = mgh

Kinetic Energy = 1/2 Mass x Velocity x Velocity
KE = 1/2mv(squared)

gravitational field strength is always 10 afaik.

Answer 3

You know better. That won't work. You need to do it on your own. Look at your book and notes. Ask questions to further explain definitions, etc, but don't ask for answers.

Answer 4

You should really do your own homework and not rely on other people, because you will never learn by getting the answers form others.