Problem 561. Find the jerk

Created by Kye Taylor

Solve Later

No, it's not the author of this problem...

Jerk is the rate of change in acceleration over time of an object. So, if given the position of an object over time in the form of a 1-by-N vector, return the indices i where there is nonzero jerk.

Super rad bonus hint: The signal you need to find the jerk of will be given by the variable sig, created with the commands

h = 0.065; % stepsize
t = -10:h:10;
sigCoefs = 2*rand(1,3)-1;
sig = polyval(sigCoefs,t);
breakPoint = randi(length(sig)-2)+1;
sig(breakPoint) = (1.01)*sig(breakPoint); % this creates a nonzero jerk

Check the signal visually with

plot(t,sig,'k.-')

Now, using just sig, determine breakPoint.

Solve

Solution Stats

92 Solutions
25 Solvers

Last Solution submitted on May 14, 2018

Last 200 Solutions

Problem Comments

4 Comments

4 Comments

Show 1 older comment

Kye Taylor on 7 Apr 2012

My apologies to the second solver of the problem... The test-suite changed so that the signal sig is no longer simply t^2. With that type of hint, someone could just difference the perturbed signal with t^2 to find the jerk.. Or someone could simply look for the point where the acceleration is negative... That's not my intent. I want a nonzero jerk. Now sig is somewhat random.

Venu Lolla on 8 Apr 2012

Kye, not a problem. I will try again. Cheers.

Kye Taylor on 8 Apr 2012

I realize that an even better signal would be one created as before except with the modification

sig(breakPoint) = (-1)^(randi(2)-1)*(1.01)*sig(breakPoint);

so that the jerk could be positive or negative...

Richard Zapor on 15 Dec 2012

Many of the solutions return multiple invalid answers. The test condition "any" allows these to pass. Suggest change "any" to "all". all(abs(findAJerk(sig) - breakPoint)<=6)

Problem Recent Solvers25

Problem Tags