Physics

Problem

A porter lifts a

15\,\text{kg}

suitcase vertically from the ground and places it on a

1.2\,\text{m}

high table at constant speed. Which statement about the work done on the suitcase is correct? a) Porter does

+1.8\times10^{2}\,\text{J}

; gravity does

0\,\text{J}

b) Porter does

+1.8\times10^{2}\,\text{J}

; gravity does

+1.8\times10^{2}\,\text{J}

c) Porter does

+1.8\times10^{2}\,\text{J}

; gravity does

-1.8\times10^{2}\,\text{J}

d) Net work on suitcase is

+1.8\times10^{2}\,\text{J}