a 25000000 gr rocket is propelled from rest by an engine that produces a 312500 kgm/s2 for 1.375s
A) What is the sleds acceleration?
B) What is the velocity after 1.375s?
A) a = F/m = 312,500/25,000 kg = 12.5 m/s^2
That is not very much acceleration for a rocket sled. Are you sure the mass is that high? That is a lot of zeroes.
B) If the acceleration, a, is constant (which it may not be since propellant is lost and mass decreases), then use
v = a t