An arrow, starting from rest, leaves the bow with a speed of 25.0 m/s. If the average force exerted on the arrow by the bow were doubled, all else remaining the same, with what speed would the arrow leave the bow?

Answer 1

F = ma, so twice the force means twice the acceleration
v^2 = 2as
so, twice the acceleration means √2 times the velocity, so 25√2 = 35.36 m/s

why not twice as fast? Because it takes less time for the arrow to leave the bow.