You have learned from last worksheet that a bumper made of aluminium has a higher carbon footprint than one made of carbon steel due to the higher embodied energy of virgin aluminium. However, we have not included the impact from energy use during the bumper's use phase. In this exercise, we will compute the carbon footprint of the bumper during use phase manually using online published data. You will then compare your estimates with output generated by SolidWorks. (a) What are the total carbon footprints from SolidWorks for the bumper made of (1) steel and (2) aluminium respectively with zero energy input from the use phase? (b) Based on the the values of carbon footprints above, which is the the preferred material when the impact from the use phase is not taken into consideration?