Question

I know all the steps but .. why they converted [ g ] to [ kg ]

The unit for mass is g

So why they converted!!

2) Calculate the kinetic energy in joules of an automobile weighing 2135 lb and traveling at 55 mph (1 mile = 1.6093 km, 1 lb-453.59 g) A) 1.2 x 104 B) 2.9 x 105 C) 5.9 x 105 D) 3.2 x 106 E) 3.2 x 106