Penjelasan:

a. the person weight in Newtons :

g = gravity (m/s²)

w = m . g

w = 40 . 10

w = 400 N

..

b. the total height that the person climbed

Known that each step has 20 cm height. The stairs have 20 steps so :

= 20 cm × 20

= 400 cm atau 4 meters

h = 4 m

...

c. how much work is done?

W = F . s

W = m . g . h

W = 40 . 10 . 4

W = 1600 J

...

d. the power output of the person running up the stairs

We know that the work to climbed up the stairs is 1600 J and need 12 seconds to climbed it. So :

P = W/t

P = 1600/12

P ≈ 133,33 W