Answer:
Total work done is W = 0 j
work done by gravity ,W = - 30000 J ON THE BASIS OF TOP SPEED
Step-by-step explanation:
given data:
mass of roller coaster is 200 kg
max height is 30 m
top speed is 30 m/s
height of section from starting point is 5 m
from work energy theorem
Work done

as there is no elastic force so we have
work done is

total work done is


W = 0 j
work done by gravitational force is W = mgh

W = - 30000 J ON THE BASIS OF TOP SPEED
here -ve sign indicate that body moves in opposite direction of gravity force