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Solved exercise · level 4 of 5

Required flow of a waterfall

Skills: Calculate

Statement

What is the flow (in m³/min) of a 10 m waterfall driving a turbine of efficiency 0.6, coupled to a generator of efficiency 0.9 delivering 13.25 kW?

P₃ = 13.25 kW · h = 10 m · ηt = 0.6 · ηg = 0.9

Parametric exercise: the values change with every draw; these are one example.

Guided problem in 4 steps: unknown, formula, units, data, result.

1 hint from Bastaya available in the lab
Solution

P₁ = P₃ / (ηt · ηg) = 24.53 kW; P₁ = m·g·h / t → mass per minute = P₁ × 60 / (9.81 × 10) = 15 × 1,000 kg, i.e. 15 m³/min.

Course sheet of the chapter : Power, energy, efficiency

This chapter is covered by the paths: General electricity, ISL-oriented exercises

Other exercises of the chapter

Simulated time00:00:00
Q = I·t-
W = P·t-

Circuit diagram CEI 60617

How does it work?

Each big hole is a circuit node: you push one leg of a component into it. The 4 small holes around it are connected to it: chips and leads plug in there.

  1. Place a component Drag it from the palette: it snaps onto the grid. R rotates it.
  2. Bridge neighbouring holes Pick the jumper chip (or C) and drag on the board: bridged holes become a single node.
  3. Draw a lead For long links and the power supply: from one big hole to another, or to a terminal.
  4. Close the loop The circuit is solved live (Ohm, Kirchhoff) and the diagram follows.

Shortcuts

Del
delete
R
rotate
C
chip brush
Esc
cancel
wheel
zoom
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fit the board
drag background
pan

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