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 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. 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 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.

1 answer

To understand how the energy of the water differs between the two drops in river A (the waterfall) and river B (the hydroelectric dam), we can analyze the potential and kinetic energy at each location.

  1. Potential Energy:

    • The potential energy (PE) of water at the top of both drops is determined by its height above the base of the drop and is calculated using the formula PE = mgh (where m is mass, g is gravitational acceleration, and h is height). Since the drops in both rivers have the same height, the potential energy at the top of the drop would be the same in both cases.
  2. Kinetic Energy:

    • When the water falls, it converts its potential energy into kinetic energy (KE), which is calculated using KE = 1/2 mv^2 (where m is mass and v is velocity). The difference between the waterfall and the hydroelectric dam lies in how that kinetic energy is utilized:
      • In river A (the waterfall), as water falls, it converts its potential energy into kinetic energy, leading to a high velocity at the bottom of the drop.
      • In river B (the hydroelectric dam), the water flows through turbines that convert that kinetic energy into mechanical energy to generate electricity, which may result in a more controlled release of water and potentially lower velocity at the bottom compared to the waterfall.

Given these points, we can determine the following:

  • The potential energy of the water would be the same at the top of the drop in both river A and river B.
  • The kinetic energy of the water would likely be greater at the bottom of the drop in river A (the waterfall) due to the free fall and lack of energy loss to turbines compared to river B where the energy is converted to generate electricity.

Thus, the correct response would be:

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.