Saturday
April 19, 2014

Homework Help: physics- TEST TMRW PLS HELP!

Posted by Anya on Sunday, December 9, 2012 at 8:45am.

Why is the following situation impossible? A librarian lifts a book from the ground to a high shelf, doing 20.0 J of work in the lifting process. As he turns his back, the book falls off the shelf back to the ground. The gravitational force from the Earth on the book does 20.0 J of work on the book while it falls. Because the work done was 20.0 J + 20.0 J = 40.0 J, the book hits the ground with 40.0 J of kinetic energy.

i don't understand why it is impossible. :/ any help appreciated!

Answer this Question

First Name:
School Subject:
Answer:

Related Questions

physics- TEST TMRW PLS HELP! - w w w . m e d i a . c h e g g c d n . c o m / m e...
physics- TEST TMRW PLS HELP! - how would i do this? -----------------A...
Chemistry :'( - (d) Which of the following sets of quantum numbers is not ...
Ged Test - All advice is welcome. I will take my Ged Test on July 16th. any ...
Physics - Momentum - Try to imagine a situation in which the form f=ma would no ...
Physics - application of Momentum - Try to imagine a situation in which the form...
Honors Physics- Help PLEASE- Test tmrw - A tritium nucleus is formed by ...
Statistics - Which one of the following test is used to compare five means, ...
Chemistry - rank the following atoms and ions in the order of expected ...
Math - This is math qustn plz help me to solve it bcz tmrw my test soreply soon ...

Search
Members