Piecewise defined function ouput array problem

Here is the problem:

t=linspace(0,50,100);
v=[];
for i =linspace(1,100)
if t(i)<10 && t(i)>~0
    v(i)= 11*t(i)^2-5*t(i)
elseif t(i)>~10 && t(i)<20
       v(i)=1100-5*t(i)
    elseif t(i)>~20 && t(i)<30 
           v(i)=50*t(i)+2*(t(i)-20)^2
    elseif t(i)>~30
               v(i)=1520*exp(-.2*(t(i)-30))
    end
end

that is my code. i cant get all my outputs to store in same vector. help!

Thanks

Peter