What happens to the pressure of the tyre if you pump it

The percent efficiency of a machine can never be 100% (or greater), because in the real world some energy is always converted into a. heat b. work c. input force d. output force

During cooling, the kinetic energy of the molecules falls. why does this happen? a.the motion of the molecules increases. b. the motion of the molecules slows down. c.the van der waals forces between molecules decrease d. the forces of attraction between the molecules are overcome.

What is the change in internal energy if 20 j of heat is released from a system and the system does 50 j of work on the surroundings? a. -70 j b. 30 j c. -30 j d. 70 j