Question

Sarita lives on 3rd floor of building at the height of 15 m. She carries her school bag weighting 5.2 kg from the ground floor to her house. Find the amount of work done by her and identify the force against which she has done work. (g=10ms-2)

Answer 1

Given -
Mass = 5.2 kg
Height = 15 m
g = 10 m/s-2
To find - Work done
Solution -
Potential Energy = mgh
= 5.2×-10×15
= -780 joules

She had done work against the force of gravity because she displaces herself from top to down

Answer 2

Solutions 

Weight= 5.2 kg
Height = 15 m

To solve the problem we use the formula 
g = 10 m/s-2

Calculations

Potential Energy = mgh
= 5.2 × -10 x 15
= -780 joules

simplified -780