Your physics book is resting in front of you on a horizontal table in the campus library. You push the book over to your friend,...... (IN THE DESCRIPTION)

Question

Your physics book is resting in front of you on a horizontal table in the campus library. You push the book over to your friend, who is seated at the other side of the table, 0.400 m m north and 0.300 m m east of you. If you push the book in a straight line to your friend, friction does -3.2 J of work on the book.

If instead you push the book 0.400 m due north and then 0.300 m due east, how much work is done by friction? Express your answer with the appropriate units.

SHOW ALL WORK STEP BY STEP PLEASE!!

Answer 1

First, we will solve for the force of friction by using the numbers given to us from the first push. Then we will us E = Fd to solve for the energy used when given the second push.

First, we know that E = 3.2 J. We also know that d will be equal to the hypotenuse of the triangle made by the 0.4 m north and 0.3 m east triangle. Lastly, we can solve for the force of friction, F_f

1. E = 3.2 J
2. d = √(0.3² + 0.4²) = 0.5 m
3. F_f = E/d = 3.2/ 0.5 = 6.4 N

Now, we will solve for the new distance pushed, and use the E = Fd equation to solve for the lost energy due to frinction:

1. d = 0.3 + 0.4 = 0.7 m
2. E = F_f*d = 6.4*0.7 = 4.48 J

Answer:

1. 4.48 J of energy lost from friction when pushing the book directly north 0.4 m, then 0.3 m east