Using Potential and Kinetic Energy Quick Check

Question

2 of 42 of 4 Items
Question
Two different rivers have drops that are the same height. In river A, this drop of the river is a waterfall. In river B, this drop has the generator for a hydroelectric dam. In what way does the energy of the water differ between the drops in the two rivers?(1 point)
Responses

The potential energy of the water would be less at the top of the drop in the waterfall river A than at the hydroelectric dam in river B.
The potential energy of the water would be less at the top of the drop in the waterfall river A than at the hydroelectric dam in river B.

The kinetic energy of the water would be less at the bottom of the drop in the waterfall river A than at the hydroelectric dam river B.
The kinetic energy of the water would be less at the bottom of the drop in the waterfall river A than at the hydroelectric dam river B.

The kinetic energy of the water would be greater at the bottom of the drop in the waterfall river A than at the hydroelectric dam in river B.
The kinetic energy of the water would be greater at the bottom of the drop in the waterfall river A than at the hydroelectric dam in river B.

The potential energy of the water would be greater at the top of the drop in the waterfall river A than at the hydroelectric dam in river B.
The potential energy of the water would be greater at the top of the drop in the waterfall river A than at the hydroelectric dam in river B.
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Answer 1

To compare the energy of the water between the two rivers, we need to consider how potential and kinetic energy are affected by the structures (a waterfall in river A and a hydroelectric dam in river B).

1. Potential Energy at the Top: Both rivers have drops of the same height, which means the potential energy at the top of the falls is the same for both river A and river B. Hence, the first response about potential energy being less in river A than B is incorrect.

2. Kinetic Energy at the Bottom:

   • In river A (the waterfall), the water is simply falling, and while it will have kinetic energy at the bottom, it won't be harnessed for any mechanical work.
   • In river B (the hydroelectric dam), the falling water is directed and used to turn turbines, which means that more of the water’s energy is converted into work in the form of electricity.

Given these considerations, the statement that accurately describes the difference is related to kinetic energy:

• The kinetic energy of the water would be less at the bottom of the drop in the waterfall river A than at the hydroelectric dam river B.

This response accurately reflects the scenario where the energy from the water at the hydroelectric dam is converted into electricity, whereas in the waterfall, that energy is simply lost to the environment as it flows down.