First let's find the acceleration required in the barrel to speed the ball up from 0 to 83 m/s in a distance of 2.17 m. We know the force the cannon exerts on the cannonball is 20000 N; if we can find this acceleration then we can use F = ma to find the mass.
We can find the acceleration using one of the kinematic equations of motion. We have:
u = initial speed = 0 m/s
v = final speed = v0 = 83 m/s
d = distance = 2.17 m
a = acceleration = ?
v² = u² + 2ad. Since u = 0, this reduces to v² = 2ad and rearranges to a = v²/2d = 83²/2*2.17 = 83²/4.34 = 1587.327 m/s².
Now F = ma, so m = F/a = (20000N)/(1587.327 m/s²) = 12.6 kg.
For part 2, use the Range Equation:
If R is the horizontal distance the cannonball travels,
v = v0 = the initial velocity = 83 m/s
g = acceleration due to gravity - 9.8 m/s²
x the launch angle relative to the horizontal, then
R = (v²sin(2x))/g.
So R = (83²sin(2*37))/9.8
= (6889sin74)/9.8 = 676 m.
So the target ship is 676 m away.