7. The graph above shows how the speed of a book changes as it slides across a table in a
straight line. Over what time interval is the
net force on the book in the opposite direc-
tion of the book's motion?
A. O s to 0.5 S
B. 0.5 s to 2.4 s
C. O s to 2.4 s
D. 2 s to 2.4 s

An engine undergoes a cycle as shown in the diagram. during a complete cycle the work done by the gas is 28.5×103 j and the energy transferred thermally out is 99.4×103 j. there are 1.5×1024 gas molecules and they have three active degrees of freedom. 6. (6 pts) during which process(es) is energy transferred thermally into the gas? a. 1→2 b. 2→3 c. 4→1 d. 1→2 and 4→1 e. none of the above