If the thermal energy of the system increases by 400 J, and 1,100 J of heat were added to the system, how much work did the system do?

700 J is the work done by the system.

Explanation:

The first law of thermodynamics is that the change in internal energy of the system is equal to the net heat transfer to the system minus the complete work performed by the system.

Where,

∆U – Change in internal energy

Q – Heat transfer to the system

Q – Work done

Here,

Given data:

∆U - 400 J

Q - 1100 J

We need to the work done by the system (W)

By applying the given values in the above equation, we get

400 = 1100 - W

W = 1100 - 400 = 700 J

ok

explanation:

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)