Suresh carried a bag containing 25 mangoes from the ground floor to the `5^(th)` floor by distributing 5 mangoes at each floor . If he starts distribution from the first floor and each mango weighs 200 g . Then calculate the total work done by the person.
(Height of each floor is 4 m , g = 10 `ms^(-2)`)

Options

A. 600 J
B. 1600 J
C. 1000 J
D. 60 J

Answer

A

Explanation

We have, work done `W = F xx s = mg xx h` (m - mass of the bag, h - height of each floor)
When the bag is in the ground floor,
`m = 25 xx 200 = 5000 g = 5` kg
When the bag is taken to the first floor,
m = 5 kg
h = 4 m
g = 10 `ms^(-2)`
Therefore, work done
`W_(1) = m xx g xx h = 5 xx 10 xx 4 = 200` J
Since 5 mangoes are given in the first floor, total number of mangoes = 20
When the bag is taken to the second floor,
`m = 20 xx 200 = 4` kg
h = 4 m
Therefore, work done
`W_(2) = m xx g xx h = 4 xx 10 xx 4 = 160` J
Since 5 mangoes are given in the second floor, total number of mangoes = 15
When the bag is taken to the third floor,
`m = 15 xx 200 = 3` kg
h = 4 m
Therefore, work done
`W_(3) = m xx g xx h = 3 xx 10 xx 4 = 120` J
Since 5 mangoes are given in the third floor, total number of mangoes = 10
When the bag is taken to the fourth floor,
`m = 10 xx 200 = 2` kg
h = 4 m
Therefore, work done
`W_(4) = m xx g xx h = 2 xx 10 xx 4 = 80` J
Since 5 mangoes are given in the fourth floor, total number of mangoes = 5
When the bag is taken to the fifth floor,
`m = 5 xx 200 = 1` kg
h = 4 m
Therefore, work done
`W_(5) = m xx g xx h = 1 xx 10 xx 4 = 40` J
Total work done,
`W = W_(1) + W_(2) + W_(3) + W_(4) + W_(5) = 200 + 160 + 120 + 80 + 40 = 600` J
Hence, the correct option is (a).