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%
Answer:
option "c" is correct
Explanation:
Physical science or Physics is the study of matter, energy and their mutual relationship.
Answer:
96.7 s
Explanation:
Time of flight in projectile can be calculated thus:
T = 2 × u × sin ϴ/ g
Where;
T = time of flight (s)
u = initial velocity (m/s)
ϴ = Angle of projectile (°)
g = acceleration due to gravity (9.8m/s²)
Based on the provided information; u = 670m/s, ϴ = 45°
Hence, using T = 2.u.sin ϴ/ g
T = 2 × 670 × sin 45° ÷ 9.8
T = 1340 × 0.7071 ÷ 9.8
T = 947.52 ÷ 9.8
T = 96.68
T = 96.7s
That's the so-called 'solar wind'.
