When energy is transferred from one part of a system to another, some of the energy is lost during the transfer and cannot be used as it was intended. Which two examples describe examples of this?

b.a device that inputs heat into a cool object

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.