15 POINTS A water wheel is a machine for changing the energy of flowing water into useful forms of power. Grindstones were once used to create products like flour and cornmeal. Before electricity was used to turn grindstones, moving water was used to turn a bladed wheel, producing energy. *

Awind
Bmechanical
Csolar
Dmagnetic

imma say b but idk

Explanation:

a. a primary source combines several different accounts of an event. b. a primary source generally benefits from having been written after an event.

explanation:

first let us lay out the formula for potential

and kinetic energy:

pe = mgh

ke = (mv^2)/2

where: m=mass, v=velocity, g=gravitational

acceleration, h=height

calculating for mass using the known values of

pe:

340j = m (9.81 m/s^2) (50ft) (1m/3.28ft)

m = 2.27 kg

the law of conservation of energy states that

energy is neither created nor destroyed. therefore, the change in kinetic

energy from 50 ft to 35 ft would be equal to the change in potential energy

from 50 ft to 35 ft. however it would be opposite in signs since one is losing

while other is gaining.

ke(35ft) – ke(50ft) = - [ pe(35ft) – pe(50ft]

ke(50ft) = 0 since the brick is initially at rest

ke(35ft) = 340j - 2.27kg (9.81 m/s^2) (35ft)

(1m/3.28 ft)

ke(35ft)

= 102.38 j