Hi
Can someone check and advise on this
potential energy of 2 tonne of water held 120m above a flood plain by a dam.
potential energy = 2032 kg (2 Tonne) x 9.81 ms x 120m
pe = 2392070.4 Joules
Convert to kilojoules
2392070.4 / 1000
pe = 2392 kJ (To four significant figures)
Many thanks
absolutely not.
You measured the height to the top of the dam, that is not where the water is. I recommend you go to the center of the dam, if you assume the cg of the water held is there. Usually, because of sloping bottom, the cg is about at the sixty percent height, but that depends on the geology of the bottom. Assume average depth of the water at 60m.
Then, PE= mgh as you did
Also, I am not certain where you got the 2032kg per 2 metric tons. I always used 1000kg is a metric ton.
Thanks Bob
I had assumed a uk tonne at 1016 kg
Mark
To calculate the potential energy of 2 tonnes of water held 120m above a flood plain by a dam, you can use the formula:
Potential energy = mass x gravitational acceleration x height
First, convert the mass of 2 tonnes to kilograms by multiplying by 1000:
Mass = 2 tonnes x 1000 kg/tonne = 2000 kg
The value of gravitational acceleration is commonly approximated as 9.81 m/s^2.
Now you can substitute the values into the formula:
Potential energy = 2000 kg x 9.81 m/s^2 x 120 m
Calculate the result:
Potential energy = 2352000 J
To convert this value to kilojoules, divide by 1000:
Potential energy = 2352000 J / 1000 = 2352 kJ
Therefore, the potential energy of 2 tonnes of water held 120m above a flood plain by a dam is 2352 kJ.