Chapter 15, Problem 20P

Describe geothermal energy and how we harness it, and evaluate its advantages and disadvantages

A dam is shaped like a parabola (y = x^2) and has a height of 150 meters. The water's density is 1000kg/m3. Pt 1. FInd the total energy stored by this dam. Pt 2. If fourty-percent of the total energy from the dam was consumed, what would be the water level's new hight? Pt 3. If a city was using this dam for its energy and consumed 12 x 107 MW of power, how much time would it take for the level of the dam to drop down to the height in part 2?

2. Consider the system described in the news: at night, when there is energy left, water is pumped from a large lake to a reservoir at 80 m above the lake level. During the day, this water is used to generate energy in a turbine located 80 m below the elevated reservoir. Considering that the water flow is always 5000 liters/s (both at the inlet of the reservoir and at the outlet) and that the pump and turbine efficiencies are 70%, what is the power (in kW) required by the pump and the power (in kW) recovered in the turbine. Data: The pipe diameter is always the same along the system (d = 0.5 m); g = 10 m/s2; γ = 9810 N/m3. Matter transport phenomena; Please make it typeable as handwriting interferes with understanding