A coal-fired power station generates electricity at night when it is not needed.Some of this energy is stored by pumping water up to a mountain lake. When there is high demand for electricity, the water is allowed to flow back through turbines to generate electricity.On one occasion, 2.05 × 108 kg of water is pumped up through a vertical height of 500 m. (i) Calculate the weight of the water.
Answers
.) Check the explanation for the answer
2.) 10 MJ
Explanation:
Given that a coal power plant station generates electricity at night when it is not needed. Some of this energy is stored by pumping water up to a mountain lake. When there is high demand for electricity, the water is allowed to flow back through a turbine to generate electricity.1- Write down the forms of initial and final energy transfer.
Solution.
The initial conversion will be :
Chemical energy is converted to mechanical energy.
The final conversion will be :
Mechanical energy is converted to electrical energy. While the electrical energy is converted to light energy.
2- On one occasion, 2000 kg of water is pumped up through a vertical height of 500 m. Calculate the gravitational potential energy. (g= 10 m/s^2)
The gravitational potential energy can be calculated by using the formula
Energy = mgh.
Where
M = mass
H = height
g = acceleration due to gravity
Substitute all the parameters into the formula
Potential Energy = 2000 × 500 × 10
Potential energy = 10000000 Joule
Potential energy = 10 MJ