# How can I calculate the acceleration if I know the time and the displacement ?

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Dragos Dascalu on 5 Apr 2018
I have a column with the exact time of each measurement, and a column with a distance between a sensor and a reflective surface. By taking the difference between two consecutive measurements I can have the time between the two and the displacement (negative or positive). How can I calculate the displacement using the derivative function ?
t1=0.2; t2=0.4;
t=t2-t1; %%%%time period
h1=150; h2=160;
d=h2-h1; %%%%%displacement v=... ? a= ... ?

Pawel Jastrzebski on 5 Apr 2018
Edited: Pawel Jastrzebski on 5 Apr 2018
Consider the following example:
t = 1:10;
h = t.^2;
dt = diff(t)
dh = diff(h)
% v - velocity
v = dh./dt
dv = diff(v)
% a - acceleration
a = dv./dt(2:end)
plot(t,h,'-ob');
hold on;
plot(t(2:end),v,'-og');
plot(t(3:end),a,'-or');
legend({'h', 'v','a'})
Outcome: Dragos Dascalu on 5 Apr 2018
why is the height dependent on time here ? I have both time and height saved in separate vectors.
Pawel Jastrzebski on 5 Apr 2018
It's just an example. I use t as the time vector and also because it's simply a vector of numbers so I used it to create the h vector of the displacement values growing exponentially. But long story short, h can be anything. In your case, use the vectors you were given.