a) The initial kinetic energy is 453 600 J.
b) The stopping distance is 648 m
c) Acceleration while stopping averages
a) The initial kinetic energy is a matter of the mass and the initial speed, and does not depend on the way in which the truck came to a halt.
b) The stopping distance is found by using conservation of energy to change the kinetic energy to frictional heat
Since the final kinetic energy is zero, the change in K is -453 600 J
c) To find acceleration, use an equation of motion