Răspuns:
R
Explicație:
L=F×d
a)30×2/2+30×(5-2)+30×(7-5)/2=
30+90+30×2/2=120+30=150N
b)40×2+(40-20)×0+20×2=
80+0+40=120N
c)4×4/2-2×2/2=8-2=6N