-- You know how much work the bow does on the arrow.
Work = (force) x (distance) = (65 N) x (0.9 m)
-- THAT's the energy the arrow got from the bow, so
THAT's the kinetic energy the arrow has as it leaves the bow.
KE = (1/2) (m) (speed)²
so (1/2) (0.075 kg) (speed)² = (65 N) x (0.9 m)
The speed is the only thing left unknown in this mess.
I'm sure you can handle it from here, and find the speed.
