The illustration above depicts a string being stretched and then released. changes in both potential and kinetic energy occur during this process. which statement most accurately describes the changes in potential or kinetic energy? a) the kinetic energy is continually increasing throughout the entire process b) the potential energy is continually increasing throughout the entire process c) the potential energy is increasing through steps a, b, & c and then decreases d) the potential energy is decreasing through steps a, b, & c and then increases

The answer is C

Explanation:

The potential energy is increasing through steps A & B, then decreases at C.

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