Answer:

Explanation:
Temperature of the house, 
Convert to rankine, 
Heat is extracted at 40°F i.e 
Calculate the coefficient of performance of the heat pump, COP

The minimum power required to run the heat pump is given by the formula:
...............(*)
Where the heat losses from the house, 
Substituting these values into * above

<span>There is a net force of 15 N allowing Levi and Clara to move the box would be your answer which is B</span>
Answer:
Explanation:
Assuming school is at the end of the 20 mile route, then
20 mi / 35 mi/hr = 0.57142...hr
which is about 34 minutes 17 seconds
Answer:

Explanation:
Ok, the average speed can be calculate with the next equation:
(1)
Basically the car cover the same distance "d" two times, but at different speeds, so:

and the total time would be the time t1 required to go from A to B plus the time t2 required to go back from B to A:

From basic physics we know:

so:


Using the previous information in equation (1)

Factoring:
(2)
Finally, replacing the data in (2)

No,because they may have more particles