A roller coaster speeds up with constant acceleration for 2.3\,\text{s}2.3s2, point, 3, start text, s, end text until it reaches a velocity of 35\,\dfrac{\text{m}}{\text{s}}35 s
m

35, start fraction, start text, m, end text, divided by, start text, s, end text, end fraction over 41\,\text{m}41m41, start text, m, end text. We want to find the initial velocity of the roller coaster before it started to accelerate.
Which kinematic formula would be most useful to solve for the target unknown?

it would be c. predictability

answer: the potential energy decreases from 379 j to 243 j

explanation:

for the law of conservation of energy, the total energy in a system must be conserved. the total energy of the system is given by the sum of kinetic (k) and potential (u) energy:

e = k + u

the total energy is e=675 j, and this does not change.

initially, the kinetic energy is k=296 j, so the potential energy is

at the end, the kinetic energy is k=432 j, so the potential energy is

so, we see that the potential energy has decreased from 379 j to 243 j.