Am nevoie de ajutor la problemele 7,8,9. Mulțumesc mult!!

Răspuns:
7. F=40N
d=1,5m
L=?
L=F×d=40×1,5=60J
8. v=60km/h=60000m/3600s=50/3m/s
F=1800N
P=?
P=L/t=F×d/t=F×v=1800×(50/3)=30000W=30KW
9. h=14m
m=350kg
t=20s
g=9,8 N/kg
L,P=?
L=mgh=350×10×14=49000J=49KJ
P=L/t=49000/20=2450W=2,45KW