Answer : The final energy of the system if the initial energy was 2000 J is, 3500 J
Solution :
(1) The equation used is,

where,
= final internal energy
= initial internal energy
q = heat energy
w = work done
(2) The known variables are, q, w and 
initial internal energy =
= 2000 J
heat energy = q = 1000 J
work done = w = 500 J
(3) Now plug the numbers into the equation, we get

(4) By solving the terms, we get




(5) Therefore, the final energy of the system if the initial energy was 2000 J is, 3500 J
180 pounds (lb) converts to 81.647 kilograms (kg).
Answer:
I. light house 1 will be warmer during the day ii. light house 2 will be warmer at night.
Explanation:
Because the land conducts heat better than water the light house farthest away from the water will get hotter during as the ground will heat up faster than the water. But this also means that the ground will lose heat faster at night where the water won't making the light house closest to the water hotter at night.