Answer:

Explanation:
Power is related to energy by the following relationship:

where
P is the power used
E is the energy used
t is the time elapsed
In this problem, we know that
- the power of the fan is P = 120 W
- the fan has been running for one hour, which corresponds to a time of

So we can re-arrange the previous equation to find E, the energy (in the form of thermal energy) released by the fan:

Answer:
52.5°C
Explanation:
The final enthalpy is determined from energy balance where initial enthalpy and specific volume are obtained from A-12 for the given pressure and state
mh1 + W = mh2
h2 = h1 + W/m
h1 + Wα1/V1
242.9 kJ/kg + 2.35.0.11049kJ/ 0.35/60kg
=287.4 kJ/kg
From the final enthalpy and pressure the final temperature is obtained A-13 using interpolation
i.e T2 = T1 + T2 -T1/h2 -h1(h2 - h1)
= 50°C + 60 - 50/295.15 - 284.79
(287.4 - 284.79)°C
= 52.5°C
- Gravitational force depends only on mass and distance, not on the state of matter.
- The forces of attraction between molecules in matter are electromagnetic in nature, not gravitational.
- These attractive forces are stronger in a solid than in a liquid than in a gas.
- Gravitational forces between molecules is completely negligible compared to the em forces.
So, key answer is inter-molecular forces of solids is stronger than liquids.