m = 1000kg Vo = 10m/s V = 0 xm= 20m
a)Eci = mVo² /2 = 100000/2 = 50000J = 50kj
b) V² = Vo² + 2a·xm ⇒ a = -2,5m/s²
Ff = ma = - 2500N L = - 2500·20 = - 50000 j (= ΔEc)
c) Eci = 50kj Ecf = 30% ·Eci = 15Kj
ΔEc = 35000J = Ff·d
d = 35000/2500 = 14m
d) Δx = 18m Vf² = Vo²+2aΔx = 100 - 90 = 10 Vf = √10 = 3,16 m/s
