Answer:
The error he made was that he didn't convert the unit of temperature to Kelvin.
The correct efficiency is 24%
Explanation:
Parameters given:
Temperature of hot reservoir = 100°C = 373 K
Temperature of cold reservoir = 10°C = 273 K
The efficiency of a heat engine is given as:
E = 1 - (Qc/Qh) = 1 - (Tc/Th)
Where
Qc = Output heat;
Qh = Input heat;
Tc = Temperature of the cold reservoir;
Th = Temperature of the hot reservoir.
=> E = 1 - (283/373)
E = 1 - 0.76
E = 0.24
In percentage,
E = 0.24 * 100 = 24%
Hence, the efficiency of the engine is actually 24%.
The error he made was that he didn't convert the temperature to Kelvin. If we leave the temperatures in °C, we have that:
E = 1 - (10/100)
E = 1 - 0.1 = 0.9
In percentage,
E = 0.9 * 100 = 90%
i think it is the second one due to the preditory descritpion of relationship A
he has to read a tripple beam balence and mesure the pltates
Answer:
1.53seconds
Explanation:
Using first equation of motion :
V=U + at
Where final velocity (V) =+8.3m/s
Initial velocity (U) =+4.4m/s
Acceleration (a) = 0.65m/s^2
time(s)=?
V=U + at
+8.3^2 = +4.4 + 0.65 * t
Making t the subject of the formula :
Therefore, t= ( +8.3 - 4.4)/0.65 = 1.53seconds
I say that is D
because it makes sense