Answer:
B. QC > 0; QH < 0
Explanation:
Given that there are two reservoir of energy.
Sign convention for heat and work :
1.If the heat is adding to the system then it is taken as positive and if heat is going out from the system then it is taken as negative.
2. If the work is done on the system then it is taken as negative and if the work is done by the system then it is taken as positive.
From hot reservoir heat is going out that is why it is taken as negative

From cold reservoir heat is coming inside the reservoir that is why it is taken as positive

That is why the answer will be
,
Answer: 7200 m
Explanation: The solution is, first convert 15 minutes to seconds.
15 mins x 60 s / 1 min = 900 s
Use the formula for speed which is v= d/t then derive for d.
d = vt
= 8 m/s ( 900s)
= 7200 m
The acceleration is 3 m/s per minute, or 0.05 m/s per second.
The moon would be bright and the earth would be darker because the sun is on the opposite side of the earth at that time and the light from it is reflecting off the moon to produce light upon the nigh also.......
You wouldn’t see the sun a night...
Unless you lived in the north/south pole