How to plot time against acceleration in my code?

Hi! I'm new to Matlab and trying to understand the basics, but I've run into a problem. I have imported data from an excel sheet about the trajectory of a small marble, but when I try the plot acceleration (ax or ay) against the time (t), all values of ax and ay are plotted against one t value! I assume this problem emerges because I am using diff(vx) to differentiate my velocity functions... How can I change my code in order to plot these values against their corresponding ts? Thanks in advance!

x=xlsread('marble excel.xlsx','B2:B26');

y=xlsread('marble excel.xlsx','C2:C26');

t=xlsread('marble excel.xlsx','A2:A26');

vx=x/t;

vy=y/t;

ax=diff(vx);

ay=diff(vy);

plot(t,ax)

hold

plot(t,ay)

Answer 1

[Image Analyst]

You need an element-by-element divide, not a matrix divide:

vx = x ./ t;
vy = y ./ t;
plot(t(1:end-1),ax)
hold all;
plot(t(1:end-1),ay)

[Skye Morrisson]

thanks! Just one question though: why is t(1:end-1) required instead of t(1:end)? I tried that as well, but a vector length error appears.

[Image Analyst]

When you do diff(), you get a vector one shorter than what you started with.