Homework answers / question archive / EGB113 Energy in Engineering Systems ME1 CONVERSION OF MECHANICAL ENERGY TO ELECTRICAL ENERGY PRE-LAB QUESTIONS Read the laboratory manual instructions for this experiment and answer these questions before the lab class PART A 1

EGB113 Energy in Engineering Systems ME1 CONVERSION OF MECHANICAL ENERGY TO ELECTRICAL ENERGY PRE-LAB QUESTIONS Read the laboratory manual instructions for this experiment and answer these questions before the lab class PART A 1

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EGB113 Energy in Engineering Systems

ME1 CONVERSION OF MECHANICAL ENERGY TO ELECTRICAL ENERGY

PRE-LAB QUESTIONS

Read the laboratory manual instructions for this experiment and answer these questions before the lab class

PART A

1.  Write an expression describing the energy conversion that occurs in Part A of the experiment.

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2.  The experiment in Part A is run using a 0.115 kg mass attached to a thread wound around the pulley. It falls from rest through a vertical height of 1.209 m in 0.66 s. Assuming that the acceleration of the mass is constant, calculate the velocity of the mass at the end of its fall. (Hint: the acceleration probably won't be 9.8 ms^-2).

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PART B

3.  In 1-2 sentences, explain the basics of hydroelectric power generation.

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4. A dam 143 m above a hydroelectric generator holds 1.6 x 10¹⁵ L of water.  If the generator is taken to be at a height of 0 m, how much potential energy is stored in the dam?

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EXPERIMENTAL OBSERVATIONS

PART A

Sketch the graph of power vs time from the computer here.  Remember to insert informative graph title, labels on axes, an indicative scale and units.

 

 

Height 1 (h₁) = _______________ (        )

m (        )	mgh (        )	t (        )	KE (        )	Energy generated (         )	Unaccounted for energy (         )	% efficiency

 

Show sample calculations for potential, kinetic and unaccounted energy here

 

 

 

 

 

 

 

 

 

Height 2 (h₂) = _______________ (        )

m (        )	mgh (        )	t (        )	KE (        )	Energy generated (         )	Unaccounted for energy (         )	% efficiency

 

Height 3 (h₃) = _______________ (        )

m (        )	mgh (        )	t (        )	KE (        )	Energy generated (         )	Unaccounted for energy (         )	% efficiency

 

Answer this question after completing Part A

On the last page of the proforma, plot efficiency vs mass for the three different heights that were investigated.  What, if anything, can you conclude from the graph?

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PART B

Diameter of water cylinder            =        2r       = ____________ (      )        

Height of Nozzle                                     h_nozzle = ____________ (      )

Initial height of water column                  h_Top    = ____________ (      )

Final height of water column                   h_Bottom = ____________ (      )

Energy Generated (area under P vs t graph)     = ____________ (      )

 

 

Sketch the graph of power vs time from the computer here.  Remember to insert informative graph title, labels on axes, an indicative scale and units.

 

 

Using Equation 5, calculate the mass of water used below:

 

 

Using Equations 4 and 2, calculate the change in potential energy:

 

 

 

Calculate the efficiency of the conversion of potential energy to electrical energy:

 

 

Answer this question after completing Part B

Why isn’t the conversion process 100% efficient?  Where does the rest of the energy go?

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Part A Graph

Plot efficiency vs mass for the three different heights that were investigated.  Remember the graph title, labels on axes, and units.

 

Appendix:    ME1   EXPERIMENTAL OBSERVATIONS

 

PART A – Mass Drop Generator

Length of thread 1 (h₁) = 1.31 m

Length of thread 2 (h₂) = 1.12 m

Length of thread 3 (h₃) = 0.66  m

Table 1 – Mass drop generator: Height 1

mass(kg)	time(s)	Electrical Energy (J)
0.02	0.77	0.1113
0.05	0.62	0.1754
0.1	0.57	0.2052

 

Table 2 – Mass drop generator: Height 2

mass(kg)	time(s)	Electrical Energy (J)
0.02	0.65	0.09936
0.05	0.543	0.1402
0.1	0.522	0.1672

 

Table 3 – Mass drop generator: Height 3

mass(kg)	time(s)	Electrical Energy (J)
0.02	0.508	0.05435
0.05	0.415	0.07908
0.1	0.392	0.08628

 

PART B- Water turbine generator

Diameter of water cylinder            =        2r       = 6 cm         

Height of Nozzle                                     h_nozzle = 15 cm

Initial height of water column                  h_Top    = 168 cm

Final height of water column                   h_Bottom = 161 cm

Area under P vs t graph                                    = 0.1575 Ws