Question

4) When filling a bicycle tire with air using a pump, the air is pushed into the tire via mechanical motion. This is similar to a cylinder (surrounding) with a movable piston that contains air (system). What is the sign of qsys and wsys if the piston is pushed downward, and heat is generated by the motion? A) +q , +w B) +q , -w C) -q , +w D) -q , - w E) not enough information

Please show your work

Answer 1

Since piston is pushed downaward, work is done on the system: w is positive (+w)

Since the heat is generated by the motion, heat is removed from the system and hence -q