I cant figure out how to make the plot show up

Nevermind.

Answer 1

[Star Strider]

Try this:

stage1BurnTimeStart=0;
stage2BurnTimeStart=165;
stage3BurnTimeStart=360;
stage3BurnTimeEnd=500;
tv = 6.5:stage3BurnTimeEnd;
rocketSpeed = zeros(size(tv));
for k = 1:numel(tv)
    t = tv(k);
    if t >= stage1BurnTimeStart & t < stage2BurnTimeStart
        specificImpulse(k) = 263;
        grossMass(k) = 2290000;
        remainingMass(k) = 13000;
        BurnTime(k)=165;
    elseif t >= stage2BurnTimeStart & t < stage3BurnTimeStart
        specificImpulse(k) = 421;
        grossMass(k) = 496200;
        remainingMass(k) = 40100;
        BurnTime(k)=360;
    elseif t >= stage3BurnTimeStart & t <= stage3BurnTimeEnd
        specificImpulse(k) = 421;
        grossMass(k) = 123000;
        remainingMass(k) = 13500;
        BurnTime(k)=500;
    end
    currentMass(k) = (grossMass(k))-((grossMass(k))-(remainingMass(k))).*t./BurnTime(k);
    rocketSpeed(k) = 9.81.*specificImpulse(k).*log(grossMass(k)./(currentMass(k)))-(t);
end

figure(1)
plot(tv,rocketSpeed)

I believe this is essentially what you intended. There are still problems that need to be addressed, however the code runs and the plot shows up!

[Amanda Reed]

Oh my gosh thank you so much!

[Star Strider]

As always, my pleasure!