Answer:
R = V / I
, R = V² / P, R = P / I²
Explanation:
For this exercise let's use ohm's law
V = I R
R = V / I
Electric power is defined by
P = V I
ohm's law
I = V / R
we substitute
P = V (V / R)
P = V² / R
R = V² / P
the third way of calculation
P = (i R) I
P = R I²
R = P / I²
Answer:
One of the reasons why flashover fires are more prevalent today than it was in the past is that homes and furniture today are made from materials that are far more combustible than those of previous years.
Explanation:
A flashover fire is the rapid ignition and combustion of all flammable materials in an enclosed vicinity in a very short period of time.
Thirty years ago, the average escape time from a house that was on fire is about sixteen and fifty seconds...that would be approximately seventeen minutes. Presently that figure is down to four minutes.
One of the reasons identified is that the internal and external appurtenances especially furniture in use today are more combustible than those of previous years. That is, as they burn, they produce more heat and disintegrate faster.
The reason identified for this is, old houses were made of more natural materials such as real wood etc whilst the furniture and curtains in modern houses are mostly from synthetic materials.
Cheers
Answer:
a) 1253 kJ
b) 714 kJ
c) 946 C
Explanation:
The thermal efficiency is given by this equation
η = L/Q1
Where
η: thermal efficiency
L: useful work
Q1: heat taken from the heat source
Rearranging:
Q1 = L/η
Replacing
Q1 = 539 / 0.43 = 1253 kJ
The first law of thermodynamics states that:
Q = L + ΔU
For a machine working in cycles ΔU is zero between homologous parts of the cycle.
Also we must remember that we count heat entering the system as positiv and heat leaving as negative.
We split the heat on the part that enters and the part that leaves.
Q1 + Q2 = L + 0
Q2 = L - Q1
Q2 = 539 - 1253 = -714 kJ
TO calculate a temperature for the heat sink we must consider this cycle as a Carnot cycle. Then we can use the thermal efficiency equation for the Carnot cycle, this one uses temperatures:
η = 1 - T2/T1
T2/T1 = 1 - η
T2 = (1 - η) * T1
The temperatures must be given in absolute scale (1453 C = 1180 K)
T2 = (1 - 0.43) * 1180 = 673 K
673 K = 946 C
Hi, you haven't provided the programing language in which you need the code, I'll just explain how to do it using Python, and you can apply a similar method for any programming language.
Answer:
1. def pyramid_volume(base_length, base_width, pyramid_height):
2. volume = base_length*base_width*pyramid_height/3
3. return(volume)
Explanation step by step:
- In the first line of code, we define the function pyramid_volume and it's input parameters
- In the second line, we perform operations with the input values to get the volume of the pyramid with a rectangular base, the formula is V = l*w*h/3
- In the last line of code, we return the volume
In the image below you can see the result of calling the function with input 4.5, 2.1, 3.0.
