Hi,
Es braucht fast nur F = m*a -> die Grundgleichung der Mechanik.
a) a = F/m = 200000 N/ 520000 kg = 5/13 m/s^2 = 0,38 m/s^2
b) v = a*t = 5/13 m/s^2*60s = 300/13 m/s = 23,08 m/s (~83 km/h)
c) a = F/m = 200000N/760000 kg = 5/19 m/s^2 -> 0,26 m/s^2
v = a*t = 5/19 m/s^2*60 = 300/19 m/s = 15,79 m/s (56,8 km/h)
Grüße