m=1;
**1;
g=9.81;
r=4;
uk=0.3;
tspan = 0:0.001:pi/2;
v0 = 5;
[t,v] = ode45((@(t,v) (g*r/v)*(sin(t)-(uk*cos(t)))+(uk*v)), tspan, v0);
q=t*180/pi;
an=((v/2).^2);
n=(g*cos(t)-an);
at=g*(sin(t)-(uk*cos(t)))+(uk*(v.^2)/4);
plot(q,(n))
hold on
index=find((n>=0)&(n<=0.01));
time=zeros(1571,1);

v_leave=v(index,1)
angle_leave=q(index,1)
x_pos=r*sin(angle_leave*pi/180)
y_pos=r*cos(angle_leave*pi/180)
while i<index
    time(i+1,1)=time(i)+(v(i+1)-v(i))/at(i,1);
    **i+1;
end
[ode45
plot(q,time)
timeleave=time(index,1)