program esfera
        implicit none
 
        integer :: i, nc
        real :: xi, xf, tp, V, t, n, k, dVdt
 
        xi=0.0
        xf=5.0
        tp=0.1
        V=0.0
        t=xi
        n=2.0
        k=0.2
 
        nc=20
 
 
        print*,t,V
 
        do i=1,nc
 
                dVdt=9.81-9.81*k*(V**n)
                V=V+tp*dVdt
                t=t+tp
 
                Print *, t, V
 
        enddo
 
        end program esfera