A man is instructed to carry a package from the base camp at B to submit A of a hill at a height of 1200 metres. The man weighs 800 N and the package weighs 200 N. If g = 10 m/s2,
(i) How much work does man do against gravity?
(ii) What is the potential energy of the package at A if it is assumed to be zero at B?
(i) Weight of the man = 800N
Weight of the package = 200N
Total weight = 800 + 200 = 1000N
Height of the hill = 1200m
g = 10m/s2
Work done = mass × height × g
= 10 × 1200 × 1000
= 12, 00, 000 J
= 12 × 105 J
(ii) Given, Weight of the package (mg) = 200N, h = 1200m
P.E = m x g x h
= 200 × 1200 × 10
= 24 × 105 J