Get Help with 2 Questions: Solar Water Heater & Air Pressure | Expert Tips

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SUMMARY

The discussion revolves around two physics problems related to a solar water heater and air pressure calculations. The first problem involves calculating the daily cost of electricity for lifting 400 liters of water through a height of 7.0 meters, using a pump with an electricity rate of $0.065/kWh. The second problem focuses on determining the pressure exerted by air at the base of a container with a volume of 100 liters, utilizing the density of air at 1.3 kg/m³ and assuming ideal gas behavior. Key equations for work done against gravity and pressure calculations are essential for solving these problems.

PREREQUISITES
  • Understanding of basic physics concepts, specifically work and energy calculations.
  • Familiarity with the formula for gravitational potential energy: Work = mass × gravity × height.
  • Knowledge of pressure calculations using the formula: Pressure = Force/Area.
  • Basic understanding of ideal gas laws and standard atmospheric conditions.
NEXT STEPS
  • Research the calculation of gravitational potential energy in fluid dynamics.
  • Learn about the relationship between pressure, volume, and temperature in ideal gases.
  • Explore the concept of work done by pumps in fluid mechanics.
  • Investigate the impact of electricity costs on operational expenses for solar water heating systems.
USEFUL FOR

Students studying physics, engineers working with fluid systems, and anyone interested in renewable energy solutions, particularly in solar water heating applications.

ABR124
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Hi

I am stuck on two questions here not sure if this is the right part of the forum to post it in, sorry in advance if it isn't. Ok the questions, my problem is that I'm not sure on the equation to use to solve these problems first problem is

A solar water heater utilizes a pump to lift 400 L of cold water per day through a vertical displacement of 7.0 meters. What is the daily cost of electricity, if the rate is set to be $0.065/kWh? Acceleration due to gravity is 9.81 m/s2 and the density of water is 0.996 g/L.

second problem
Calculate the pressure exerted by the air to the base of the column (area is 1.0 m2). The density of air can be taken a 1.3 kg/m3 and the volume of the container is 100L. Assume ideal gas behaviour and standard conditions (atmospheric pressure and 25 degrees C)

Ok I don't really know where to start with these problems and I'm not looking for the solution to these problems just maybe someone to help me on the right track or maybe to provide me with the equations to do these problems. Thanks in advance.
 
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Hint to start you on first problem: how much work do you do on 1 liter of water lifting it that height?
 

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