Which of the following situations would cause the greatest decrease in the motion of molecules in a system?
a. q = -50 j, w = -50 j
b. q = +50 j, w = +50 j
c. q = -50 j, w = +50 j
d. q = +50 j, w = -50 j

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

Imagine you are standing in the antarctic during the southern hemisphere summer. the sky is clear and blue. there are no clouds in the sky. your shadow is cast on the icy ground. what is the color of the shadow?

You hang a book bag on a spring scale and place the bag on a platform scale so that the platform scale reads 23.7n and the spring scale reads 13.8n. what is the magnitude of the force that earth exerts on the bag?