Question

zad 1 i 2 bez 3

Answer 1

zad.1.

m = 300 kg

h = s = 12 m

g = 9,81 m/s² = 10 m/s²

W = ?

W = F * s

F = m * g

W = m * g * s

W = 300 kg * 10 m/s² * 12 m

W = 36000 J = 3, 6 kJ    ; 1 kJ = 1000 J

 

zad.2.

P = 250 W

m = 150 kg

h = s = 10 m

g = 10 m/s²

t = ?

 

P = W / t

W = F * s

P = F * s/t

F = m * g

P = m * g * s/t

P * t = m *g *s

t =m * g * s/P

t =  150 kg * 10 m/s² * 10 m /250 W

t = 15000 J/250 W

t = 6 s

[J/W] = [J/J/s] = [ s]