question_answer

The work done by a person in carrying a box of mass 15 kg through a vertical height of 5 m is 4900J.The mass of the person is ?????

Answer:

Mass of box, m = 15 kg; Mass of the person, M = ? height, \[h=5\,m;\,\,g=9.8\,\,m/{{s}^{2}}\] Work done, W = 4900 J We know, \[W=(M+m)g\,\,h\] \[\Rightarrow 900=(M+15)\times 9.8\times 5\] \[\Rightarrow M+15=100\Rightarrow 85\,\,kg.\]