My problem is as follows: A body of mass 2 kilograms moves on a circle of radius 2 meters, making one revolution every 5 seconds. Find the centripetal force acting on the body.
What I tried originally was $F_c=\frac{mv^2}{r}$, where $v=\frac{4\pi}{5sec}$, $m=2kg$ and $r=2$, but the program didn't accept the answer I got ($6.3165N$). I then tried what I saw here, but I didn't understand what "t" was in his equations.
I also found this here, which is the problem from my textbook. Unfortunately, I don't have the answer key for it, so I cannot see what the correct answer is. Apparently, this guy's work is incorrect, but the person who states so didn't post the corrected version.
Any help would be greatly appreciated, since I'm not quite sure what else to try.
hint
$$F_c=mr\omega^2$$ with $$\omega=\frac {v}{r}=\frac {d\theta}{dt}=\frac {2\pi}{5} $$
which gives $$F_c=\frac {16}{25}\pi^2\approx 6.3 N $$