Energy Transfers occurs continually in natural systems. For today's lesson, you will investigate the transfer of energy in waterfalls.
TME = KE + PE
The total mechanical energy of a system is a sum of the kinetic and potential energies in that system.
TME = KE + PE
The total mechanical energy of a system is a sum of the kinetic and potential energies in that system.
Waterfall
Do an internet search for waterfalls. You may select any waterfall if you can find the following information about it:
1. a photo
2. the height of the water fall (be sure to include units . . . Is the height given to you in feet? in meters?)
3. the volume of water that goes over it (flow rate)
- Be sure that you have units for this, too . . . it is likely to be provided in Cubic Feet per Second (CFS)
or Cubic Meters per Second (CMS)
- If you are having difficulty finding the flow rate for the waterfall, you can try searching for the flow rate of the . river. See me if you can't find either type of information. We may be able to make a reasonable estimate or . you may have to choose another waterfall.
Analysis:
1. For one kilogram of water, find the velocity at the bottom of the waterfall.
According to the Law of Conservation of Energy, the total energy will be the same whether the water is at the top or bottom of the falls. Therefore, the Gravitional Potential Energy of one kilogram of water will transferred to KE at the bottom of the falls. Since you can use Eg = mgh to find the energy at the top, you can set that equal to the KE at the bottom and solve for velocity. Recall that EK = 1/2 m v v
If you're up for a challenge, try this:
When you complete that, find the energy transferred by the falling water in a given period of time. You may choose the time period - minute, hour, day.
The water will have gravitational potential energy at the top of the falls. You will need to determine the mass of the amount of the water that falls. Next, use Eg = mgh to find the energy transferred by the falling water.
1. a photo
2. the height of the water fall (be sure to include units . . . Is the height given to you in feet? in meters?)
3. the volume of water that goes over it (flow rate)
- Be sure that you have units for this, too . . . it is likely to be provided in Cubic Feet per Second (CFS)
or Cubic Meters per Second (CMS)
- If you are having difficulty finding the flow rate for the waterfall, you can try searching for the flow rate of the . river. See me if you can't find either type of information. We may be able to make a reasonable estimate or . you may have to choose another waterfall.
Analysis:
1. For one kilogram of water, find the velocity at the bottom of the waterfall.
According to the Law of Conservation of Energy, the total energy will be the same whether the water is at the top or bottom of the falls. Therefore, the Gravitional Potential Energy of one kilogram of water will transferred to KE at the bottom of the falls. Since you can use Eg = mgh to find the energy at the top, you can set that equal to the KE at the bottom and solve for velocity. Recall that EK = 1/2 m v v
If you're up for a challenge, try this:
When you complete that, find the energy transferred by the falling water in a given period of time. You may choose the time period - minute, hour, day.
The water will have gravitational potential energy at the top of the falls. You will need to determine the mass of the amount of the water that falls. Next, use Eg = mgh to find the energy transferred by the falling water.
SHARE YOUR WORK
To turn in your work, you will either email me your PPT or post a screen shot of the PPT slide that you made on the padlet below.
To take a screen shot, you hit control, shift and 3 together. An image file will appear on your desktop. Post that image to the padlet. Click on the link to access the padlet.
To take a screen shot, you hit control, shift and 3 together. An image file will appear on your desktop. Post that image to the padlet. Click on the link to access the padlet.
A few years ago, Physics students had a similar assignment. Take a look at their work if you want to, but keep in mind that your assignment is a little different.