Explanation:
Since, it is mentioned the there occurs no change in the temperature. This also means that there will occur no change in thermal energy of the system.
Hence, 
= 0. And, as = 0 then there will be no work involved. This means that total energy added to the house will return to the outside air as heat.
Therefore,
Q = -(19000 J + 2000 J)
= -21000 J
or, |Q| = 21000 J
Thus, we can conclude that the magnitude of the energy transfer between the house and the outside air is 21000 J.
Answer: Whenever two objects are touching, they usually exert forces on each other. The force of gravity, on the other hand, is an example of a force that exists between objects without them having to be in contact. Objects with mass exert forces on each other via the force of gravity.
HOPE IT HELPED:) HAVE A NICE DAY
Get a pull chord light switch installed in her bathroom by a qualified electrician asap. Meanwhile, keep hands as dry as possible, and try not to go near that switch until it's either been properly earthed, or whatever the problem actually is, and get qualified advice on what the problem is. Don't have wet feet either, and don't stand in puddles of water whilst operating - i she has to - the switch. 250V AC mains can be lethal, and at least painful.
