Pumping up a bicycle tyre makes the pump warm because:

  1. heat flows in from outside
  2. friction only
  3. work is done on the air, raising its internal energy
  4. air does work on the pump
Answer

C) work is done on the air, raising its internal energy

Compression heats the gas. SLO P-11-C-07 · Understanding

Physics MCQ · More Kinetic Theory and First Law of Thermodynamics MCQs · Practise