**Answer:**

And Im still going with B..

**Answer:**Antifreeze/coolant

**Explanation:** keeps your engine cool in warm weather and keeps it from freezing up in the winter. A 50-50 mix of full strength coolant and water generally protects to around -30 degrees Fahrenheit. Make sure you check with the supplier or your owner's manual for the correct formulation

**Answer:**

15.8529 kW

**Explanation:**

Rate of heat loss = 60000 Btu/h

Internal heat gain = 6000 Btu/h

Rate of heat required to be supplied

Converting 54000 Btu/h to kW (kJ/s)

1 Btu = 1.05506 kJ

1 h = 3600 s

**∴ Required rated power of these heaters is 15.8529 kW**

Heater control valves can not leak coolant

it is true

**Answer:**

the final temperature would have been 2.81 °C if the pressure drop was 2 psi

**Explanation:**

if we assume that is no change in volume, there are not leaks present and also that the gas inside the football behaves as an ideal gas, we have:

initial state) P1 V = n R T1

final state) P2 V = n R T2

where P = absolute pressure , V = volume occupied by the gas, n = number of moles of gas, R = ideal gas constant T= absolute temperature

therefore since V= constant (constant volume) and n= constant ( no leaks), if we divide both equations

P2/P1 = T2/T1

therefore

T2 = T1 *(P2/P1)

since P1 absolute = P1 relative + P atmospheric (14.7 psi) = 12.5 psi + 14.7 psi = 27.2 psia

also P2 = P1 - 2 psi = 25.2 psia

T1 = 24.7°C + 273 °C = 297.7 K

therefore

T2 = T1 * (P2/P1) = 297.7 K ( 25.2 psia/27.2 psia) = 275.81 K

thus T2 = 275.81 K = 2.81 °C