Answer:
Option C : 290 J
Explanation:
We can use conservation of energy to estimate the kinetic energy when the object hits the ground:
When the object is at its initial height of 15 meters, it velocity is zero (falls from this position), therefore the total energy it possesses is due to potential energy given by the expression:
Joules
At the moment the object hits the ground from its free fall, its potential energy is zero, while its kinetic energy must equal the rest. So at that moment the object's kinetic energy must be 294 Joules.
Answer:
100°C
Explanation:
The heat gained by the ice equals the heat lost by the steam, so the total heat transfer equals 0.
Heat lost by the steam as it cools to 100°C:
q = mCΔT
q = (3 kg) (2.00 kJ/kg/K) (100°C − 120°C)
q = -120 kJ
Total heat so far is negative.
Heat lost by the steam as it condenses:
q = -mL
q = -(3 kg) (2256 kJ/kg)
q = -6768 kJ
Heat absorbed by the ice as it warms to 0°C:
q = mCΔT
q = (6 kg) (2.11 kJ/kg/K) (0°C − (-40°C))
q = 506.4 kJ
Heat absorbed by the ice as it melts:
q = mL
q = (6 kg) (335 kJ/kg)
q = 2010 kJ
Heat absorbed by the water as it warms to 100°C:
q = mCΔT
q = (6 kg) (4.18 kJ/kg/K) (100°C − 0°C)
q = 2508 kJ
The total heat absorbed by the ice by heating it to 100°C is 5024.4 kJ.
If the steam is fully condensed, it loses a total of -6888 kJ.
Therefore, the steam does not fully condense. The equilibrium temperature is therefore 100°C
Moon phases repeat every 29.531 days, because as the moon revolves around the Earth, the amount of the moon's lighted half that we can see changes steadily.