The force of gravity is much weaker than the strong nuclear force. But the strong nuclear force only acts over short distances, such as within the nuclues. The gravitational force can act over infinite distance.
“Asexual reproduction is a type of reproduction by which offspring arise from a single organism, and inherit the genes of that parent only; it does not involve the fusion of gametes, and almost never changes the number of chromosomes.” -Wikipedia
The velocity is 60 because you divide your distance by your time (240÷4=60)
Force=mass x acceleration
f= 0.5 x40
f=20N