Hi there!
We can use the following:
W = ΔKE = F · d
Find the work done on the cart:
W = 200 · 10 = 2000 J
Now, this is equal to the change in kinetic energy of the object. Its initial kinetic energy is 0 J since it starts from rest, so:
2000J = KEf - KEi
KE is given as:
2000J = 1/2(55)v²
4000 = 55v²
√(4000/55) = 8.53 m/s