A block of mass 2.29 kg is pulled to the right along a horizontal frictionless path by a constant force of 13.7 N.
The acceleration due to the force is 13.7/2.29 m/s^2
Use the relation v^2 - u^2 = 2*a*s where u is the initial speed, v is the final speed, a is the acceleration and s is the distance moved.
In the problem, v has to be determined. u = 0, s = 3.99 and a has been derived to be 13.7/2.29
v^2 = 2*13.7/2.29*3.99
=> v^2 = 47.74
v = 6.909 m/s
The speed of the block after it has moved 3.99 m is 6.909 m/s.