Question

Duży pociag towarow ma mase 15000 ton. Jesli lokomotywan moze ten sklad pchac z sila 750000 N to jak dlugo trwa rozpedzenie pociagu od 0 do 80 km/h?

Answer 1

M = 15000t = 15 * 10^6 kg
v0 = 0
v = 80 km/h = 200/9 m/s = 22,(2) m/s
Δv = v - v0 = v
F=750000N = 75 * 10^4 N
t = ?

F = m*a => a = F/m
a = Δv/t => t = Δv/a = v/a
t = v/a = v/F/m => t = v * m / F
t = 80 * 15 * 10^6 / 75 * 10^4 = 1200 * 10^2 / 75 = 120000 / 75 = 1600s