A winch pulls a 50\,\text{kg} crate across a frictionless horizontal surface by delivering constant power of 200\,\text{W} for 5.0\,\text{s}. If the crate starts from rest, what is its speed at t = 5.0\,\text{s}?
a) 8.9m/s
b) 20m/s
c) 6.3m/s
d) 4.5m/s