When an 81 kg adult uses a spiral staircase to climb to the second floor of his house, his gravitational potential energy increases by 2 x 10^3 J. By how much does the potential energy of an 18 kg child increase when the child climbs a normal staircase to the second floor? a. 638 Nb. 478 Nc. 319 Nd. 532 Ne. 444 N

option (e) is correct.

Explanation:

mass of adult, M = 81 kg

Gravitational Potential energy of adult, U = 2000 J

Let the height raised is h.

U = mass of adult x g x h

2000 = 81 x 9.8 x h

h = 2.52 m

mass of adult, m = 18 kg

height raised, h = 2.52 m

Potential energy of child, U' = m x g x h

U' = 18 x 2.52 x 9.8 = 444.44 J

Thus, option (e) is correct.