A block is moved from rest through a distance at `4 m` along a string line path . The mass of the block is `5 kg` and the force acting on it is `20N`. If the kinetic energy acquired by the block be `40 J`, at what angle to the path is the force acting?
A. `30^(@)`
B. `45^(@)`
C. `60^(@)`
D. None of these