kinematics equation problem

[raincheck]

"An experimental rocket sled can be accelerated at a constant rate from rest to 1600 km/hr in 1.8 s. What is the magnitude of the required net force if the sled has a mass of 500 kg?"

I know I have to use
[sum of the] F = ma

and i was trying
= 500 x 1600,
but I'm sure there's something else I have to do to get the right answer, since this isn't working..

[OlderDan]

Look again at the definition of acceleration. You have used velocity in place of acceleration. Be careful with your units. km/hr is not m/s.

[QuantumCrash]

If you are having trouble, try solving it in terms of kinematics first. After you find the acceleration, then you can do what you did.