Storing while loop results in an array and plotting

Hello, I have this simple code simulating free fall. The while loop works fine in the first case but i need to plot the results. I tried to put the y and v values in arrays but the results i get are wrong. How do i fix that?

clear, clc, close all, format long

% Initial values and constants

g = 10;
y = 100;
v = 0;
t = 0;
h = 0.1;

fprintf('\n\tt (sec)\t\ty (m)\t\tv (m/sec)\n')

	t (sec)		y (m)		v (m/sec)

fprintf('\n\t%.2f\t\t%.2f\t\t%.2f\n',t,y,v)

	0.00		100.00		0.00

while y >= 0
    y = y + h*v;
    v = v - h*g;
    t = t + h;
    fprintf('\n\t%.2f\t\t%.2f\t\t%.2f\n',t,y,v)
end

	0.10		100.00		-1.00

	0.20		99.90		-2.00

	0.30		99.70		-3.00

	0.40		99.40		-4.00

	0.50		99.00		-5.00

	0.60		98.50		-6.00

	0.70		97.90		-7.00

	0.80		97.20		-8.00

	0.90		96.40		-9.00

	1.00		95.50		-10.00

	1.10		94.50		-11.00

	1.20		93.40		-12.00

	1.30		92.20		-13.00

	1.40		90.90		-14.00

	1.50		89.50		-15.00

	1.60		88.00		-16.00

	1.70		86.40		-17.00

	1.80		84.70		-18.00

	1.90		82.90		-19.00

	2.00		81.00		-20.00

	2.10		79.00		-21.00

	2.20		76.90		-22.00

	2.30		74.70		-23.00

	2.40		72.40		-24.00

	2.50		70.00		-25.00

	2.60		67.50		-26.00

	2.70		64.90		-27.00

	2.80		62.20		-28.00

	2.90		59.40		-29.00

	3.00		56.50		-30.00

	3.10		53.50		-31.00

	3.20		50.40		-32.00

	3.30		47.20		-33.00

	3.40		43.90		-34.00

	3.50		40.50		-35.00

	3.60		37.00		-36.00

	3.70		33.40		-37.00

	3.80		29.70		-38.00

	3.90		25.90		-39.00

	4.00		22.00		-40.00

	4.10		18.00		-41.00

	4.20		13.90		-42.00

	4.30		9.70		-43.00

	4.40		5.40		-44.00

	4.50		1.00		-45.00

	4.60		-3.50		-46.00

subplot(2,1,1), plot(t,y), grid on
subplot(2,1,2), plot(t,v), grid on

% Alternative way - putting values in array

% Initial values and constants

g = 10;
i = 1;
y(i) = 100;
v(i) = 0;
t(i) = 0;
h = 0.1;

fprintf('\n\tt (sec)\t\ty (m)\t\tv (m/sec)\n')

	t (sec)		y (m)		v (m/sec)

fprintf('\n\t%.2f\t\t%.2f\t\t%.2f\n',t,y,v)

	0.00		100.00		0.00

while y >= 0
    y(i+1) = y(i) + h*v(i);
    v(i+1) = v(i) - h*g;
    t(i+1) = t(i) + h;
    i = i + 1;
end
fprintf('\n\t%.2f\t\t%.2f\t\t%.2f\n',t,y,v)

	0.00		0.10		0.20

	0.30		0.40		0.50

	0.60		0.70		0.80

	0.90		1.00		1.10

	1.20		1.30		1.40

	1.50		1.60		1.70

	1.80		1.90		2.00

	2.10		2.20		2.30

	2.40		2.50		2.60

	2.70		2.80		2.90

	3.00		3.10		3.20

	3.30		3.40		3.50

	3.60		3.70		3.80

	3.90		4.00		4.10

	4.20		4.30		4.40

	4.50		4.60		100.00

	100.00		99.90		99.70

	99.40		99.00		98.50

	97.90		97.20		96.40

	95.50		94.50		93.40

	92.20		90.90		89.50

	88.00		86.40		84.70

	82.90		81.00		79.00

	76.90		74.70		72.40

	70.00		67.50		64.90

	62.20		59.40		56.50

	53.50		50.40		47.20

	43.90		40.50		37.00

	33.40		29.70		25.90

	22.00		18.00		13.90

	9.70		5.40		1.00

	-3.50		0.00		-1.00

	-2.00		-3.00		-4.00

	-5.00		-6.00		-7.00

	-8.00		-9.00		-10.00

	-11.00		-12.00		-13.00

	-14.00		-15.00		-16.00

	-17.00		-18.00		-19.00

	-20.00		-21.00		-22.00

	-23.00		-24.00		-25.00

	-26.00		-27.00		-28.00

	-29.00		-30.00		-31.00

	-32.00		-33.00		-34.00

	-35.00		-36.00		-37.00

	-38.00		-39.00		-40.00

	-41.00		-42.00		-43.00

	-44.00		-45.00		-46.00

subplot(2,1,1), plot(t,y), grid on
subplot(2,1,2), plot(t,v), grid on

Answer 1

[Torsten]

Why do you think the results you get from the second part of your code are wrong ?

g = 10;
y(1) = 100;
v(1) = 0;
t(1) = 0;
h = 0.1;
i = 1;
while y(i) >= 0
    i = i + 1;
    y(i) = y(i-1) + h*v(i-1);
    v(i) = v(i-1) - h*g;
    t(i) = t(i-1) + h;
    fprintf('\n\t%.2f\t\t%.2f\t\t%.2f\n',t(i),y(i),v(i))
end

	0.10		100.00		-1.00

	0.20		99.90		-2.00

	0.30		99.70		-3.00

	0.40		99.40		-4.00

	0.50		99.00		-5.00

	0.60		98.50		-6.00

	0.70		97.90		-7.00

	0.80		97.20		-8.00

	0.90		96.40		-9.00

	1.00		95.50		-10.00

	1.10		94.50		-11.00

	1.20		93.40		-12.00

	1.30		92.20		-13.00

	1.40		90.90		-14.00

	1.50		89.50		-15.00

	1.60		88.00		-16.00

	1.70		86.40		-17.00

	1.80		84.70		-18.00

	1.90		82.90		-19.00

	2.00		81.00		-20.00

	2.10		79.00		-21.00

	2.20		76.90		-22.00

	2.30		74.70		-23.00

	2.40		72.40		-24.00

	2.50		70.00		-25.00

	2.60		67.50		-26.00

	2.70		64.90		-27.00

	2.80		62.20		-28.00

	2.90		59.40		-29.00

	3.00		56.50		-30.00

	3.10		53.50		-31.00

	3.20		50.40		-32.00

	3.30		47.20		-33.00

	3.40		43.90		-34.00

	3.50		40.50		-35.00

	3.60		37.00		-36.00

	3.70		33.40		-37.00

	3.80		29.70		-38.00

	3.90		25.90		-39.00

	4.00		22.00		-40.00

	4.10		18.00		-41.00

	4.20		13.90		-42.00

	4.30		9.70		-43.00

	4.40		5.40		-44.00

	4.50		1.00		-45.00

	4.60		-3.50		-46.00

y = y(1:end-1);
v = v(1:end-1);
t = t(1:end-1);
subplot(2,1,1), plot(t,y), grid on
subplot(2,1,2), plot(t,v), grid on

[Torsten]

The below code linearly interpolates the time point t0 when y becomes 0 between the last two values for y, namely (t(end-1),y(end-1)) and (t(end),y(end)) with y(end-1) > 0 and y(end) <= 0:

g = 10;
y(1) = 100;
v(1) = 0;
t(1) = 0;
h = 0.1;
i = 1;
while y(i) > 0
    i = i + 1;
    y(i) = y(i-1) + h*v(i-1);
    v(i) = v(i-1) - h*g;
    t(i) = t(i-1) + h;
    fprintf('\n\t%.2f\t\t%.2f\t\t%.2f\n',t(i),y(i),v(i))
end

	0.10		100.00		-1.00

	0.20		99.90		-2.00

	0.30		99.70		-3.00

	0.40		99.40		-4.00

	0.50		99.00		-5.00

	0.60		98.50		-6.00

	0.70		97.90		-7.00

	0.80		97.20		-8.00

	0.90		96.40		-9.00

	1.00		95.50		-10.00

	1.10		94.50		-11.00

	1.20		93.40		-12.00

	1.30		92.20		-13.00

	1.40		90.90		-14.00

	1.50		89.50		-15.00

	1.60		88.00		-16.00

	1.70		86.40		-17.00

	1.80		84.70		-18.00

	1.90		82.90		-19.00

	2.00		81.00		-20.00

	2.10		79.00		-21.00

	2.20		76.90		-22.00

	2.30		74.70		-23.00

	2.40		72.40		-24.00

	2.50		70.00		-25.00

	2.60		67.50		-26.00

	2.70		64.90		-27.00

	2.80		62.20		-28.00

	2.90		59.40		-29.00

	3.00		56.50		-30.00

	3.10		53.50		-31.00

	3.20		50.40		-32.00

	3.30		47.20		-33.00

	3.40		43.90		-34.00

	3.50		40.50		-35.00

	3.60		37.00		-36.00

	3.70		33.40		-37.00

	3.80		29.70		-38.00

	3.90		25.90		-39.00

	4.00		22.00		-40.00

	4.10		18.00		-41.00

	4.20		13.90		-42.00

	4.30		9.70		-43.00

	4.40		5.40		-44.00

	4.50		1.00		-45.00

	4.60		-3.50		-46.00

t0 = (y(end)*t(end-1)-y(end-1)*t(end))/(y(end)-y(end-1));
t0 - t(end-1)

ans = 0.0222

y(end) = 0;
v(end) = v(end-1) - (t0-t(end-1))*g;
t(end) = t0;
subplot(2,1,1), plot(t,y), grid on
subplot(2,1,2), plot(t,v), grid on

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