Identify characteristics of energy from the Sun. Check all that apply.
2 answers:
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Answer:
Qt = 940500 [J]
Explanation:
In order to solve this problem and understand it well, we must analyze that the ice melts or changes phase at a temperature of 0 [°c], then the water at a temperature of 100 [°C] evaporates or changes phase. That is, we have 5 different stages of water (initially in the form of ice), which are:
-) From -30 [°C] to 0 [°C] = Sensible change of temperature
-) At 0 [°C] = Latent heat of melting ice = 334 x 10³ [J/kg]
-) From 0 [°C] to 100 [°C] = Sensible change of temperature
-) At 100 [°C] = Latent heat of fusion for water = 2260 x 10³ [J/kg]
-) From 100 [°C] to 130 [°C] = Sensible change of temperature (superheating)
We can calculate the sensible heat of any process with the following expression:
where:
Q = heat or thermal energy [J]
m = mass of the body or substance = 300 [g]
Cpw = specific heat of the water = 4180 [J/kg*°C]
Cpi = specific heat of the ice = 2090 [J/kg*°C]
Tfinal = final temperature of the process [°C]
Tinicial = initial temperature of the process [°C]
And for some latent heat process, we can calculate the thermal energy using the following expression:
where:
Dhfus/eva = Fusion heat or latent heat [J/kg]
So, we need to calculate the fice processes.
And the final step is the sum of all the five heat processes.
Answer:
<em>The angle introduces an error on the mesure of the weight</em>
Explanation:
<u><em>Weight and Normal Forces</em></u>
When an object is resting on a horizontal surface, its weight is directed downwards and the normal force has the same magnitude and opposite direction, i.e. directed upwards. When some angle α exists between the surface and the horizontal plane, the scale keeps 'feeling' the Normal force, but it's not equal to the weight anymore, but to the perpendicular component of the weight to the surface where the scale is placed. It can be found that the component of the weight is m.g.cosα
If, for example , the real measure is
That is, 98.5% of the correct weight. So it's important to measure weight on horizontal surfaces