Issue

This Content is from Stack Overflow. Question asked by Silverlik

I’m trying to create a function which returns an array of the velocity per second for a free falling object. The input argument for the function is the height h. Also, if the object hits the ground before 1 second, it should return the velocity for the time it hits the ground.

Example: If the object falls from 80 meters, the function should return

v =

9.8 19.6 29.4 39.2

My attempt looks like this:

function freefall(h)

g = 9.8;               % gravity acceleration
h_t = linspace(0,h);   % the height should start from 0 to input height h
t = sqrt(2.*h_t/g);      % time for the free fall
n=0;

if t < 1
    velocity = sqrt(2*g*h)
    disp(velocity)    
else

 for time = n+1    % An attempt to try making t into integers(tried floor(t) but didn't work)
     
    v = g.*time      
    
    while time <= t   % Don't want the time to exceed the amount of time it takes for object to land
        disp(v)
    end
 end
end

end

The output just becomes v = 9.82, and I’m out of ideas to try and make this work.

Solution

I don’t have matlab or scilab at the moment so I fiddled around using online scilab to write some test code. Here what I came up with:

function freefall(h)
    g = 9.8;
    
    t = floor(sqrt(2*h/g));
    if t < 1
       t = 1;
    
    t_mat = linspace(1, t, t);
    
    t_mat = g * t_mat;
    return t_mat;
end

You can then call that function this way:

disp(freefall(80));

What’s missing on your code is rather to limit the increments of linspace, for some odd reason you tried to compare a vector to a scalar (that if t < 1 on your code), and finally your function did not return an answer, instead it prints it.

¯\(ツ)/¯ correct me if I’m wrong, I haven’t write any matlab code for like 6 years.

Note: that online scilab doesn’t seem to support function so, you have to use bare code without the function block. You can replace that return with disp(t_mat).

This Question was asked in StackOverflow by Silverlik and Answered by Bagus Tesa It is licensed under the terms of CC BY-SA 2.5. - CC BY-SA 3.0. - CC BY-SA 4.0.