Answer:
15.24°C
Explanation:
The quality of any heat pump pumping heat from cold to hot place is determined by its coefficient of performance (COP) defined as
Where Q_{in} is heat delivered into the hot place, in this case, the house, and W is the work used to pump heat
You can think of this quantity as similar to heat engine's efficiency
In our case, the COP of our heater is
Where T_{house} = 24°C and T_{out} is temperature outside
To achieve maximum heating, we will have to use the most efficient heat pump, and, according to the second law of thermodynamics, nothing is more efficient that Carnot Heat Pump
Which has COP of:
So we equate the COP of our heater with COP of Carnot heater
Rearrange the equation
Solve this simple quadratic equation, and you should get that the lowest outdoor temperature that could still allow heat to be pumped into your house would be
15.24°C
Answer:
This doesn't represent an equilibrium state of stress
Explanation:
∝ = 1 , β = 1 , y = 1
x = 0 , y = 0 , z = 0 ( body forces given as 0 )
Attached is the detailed solution is and also the conditions for equilibrium
for a stress state to be equilibrium all three conditions has to meet the equilibrum condition as explained in the attached solution
Answer:
As the asteroid falls closer to the Earth's surface its <u>Gravitational</u> <u>Potential</u> energy <em>decreases</em> and its <u>Kinetic</u> energy <em>increases</em>.
Answer:
>>pounds=13.2
>>kilos=pounds/2.2
Explanation:
Using Matlab to write the program, consider at any time when the weight in pounds is 13.2 lb, this variable of weight is created in MATLAB by typing >>pounds=13.2. To convert it from lb to Kg, we simply divide it by 2.2 hence the second command to created is kilos. For this, the output of the program will be 6 Kg.
Answer:
Since the farmer wants to buy a 10 kg bag of fertilizer, he should buy it from merchant A. However, Merchant A and B are selling at the same price for a unit value. In other words, Both Merchant A and B are selling 1kg of dry fertilizer for $1.
Explanation:
Which merchant has the better deal means which merchant offers the farmer a better deal.
For Merchant A, 10 kg bag = $10
meaning it contains a real 10 kg bag of dry fertilizer which the farmer can use without losing any Kg to drying.
While for Merchant B, 10 kg bag = $8
where the 10kg = 80% dry fertilizer + 20% water content
But the farmer can only use the solid constituents of the bag which means,
Merchant B is giving 80/100 x 10Kg of dry fertilizer for $8
That is, 8kg for $8
Since the farmer wants to buy a 10 kg bag of fertilizer, he should buy it from merchant A. However, Merchant A and B are selling at the same price for a unit value. In other words, Both Merchant A and B are selling 1kg of dry fertilizer for $1.
