missing/incorrect use of math operators?

Good evening,

I am new to matlab, and was wondering if someone could look at my code to see if I am incorrectly using/missing some sort of math operator (i.e. I've noticed sometimes you need a ./ verses a / for divison).

My code produces a table however, the time of flight column should be consistantly increasing in a value, and my striking velocity values are too large. I am wondering if I am missing something in my code.

Thank you for your assistance

Below is my code:

k3 = 0.5;
Vx_o = 2296;
t = 0;
 
for i = 1:6
    x(i) = (i-1)*200*3;                          % range in feet
    Vx(i) = (sqrt(Vx_o) - ((k3/2)*x(i)))^2;    % x velocity
    t(i) = (x(i)/Vx_o)*sqrt(Vx_o/Vx(i));  % time
 
end
 
T = table(x(:)/3, x(:), Vx(:), t(:), 'VariableNames',{'yards', 'feet', 'striking velocity', 'time of flight'})

Answer 1

[Geoff Hayes]

Jocelyn - why should the time of flight value be increasing in value? Is it because it is dependent upon the previous value? Do you want add the previous value to this current like

for i = 1:6
    x(i) = (i-1)*200*3;                          % range in feet
    Vx(i) = (sqrt(Vx_o) - ((k3/2)*x(i)))^2;    % x velocity
    t(i) = (x(i)/Vx_o)*sqrt(Vx_o/Vx(i));  % time
    
    if i > 1
        t(i) = t(i) + t(i-1);  % is this what you want?
    end
 
end

As for the striking velocity being too large, consider the line

Vx(i) = (sqrt(Vx_o) - ((k3/2)*x(i)))^2;   

You are taking sqrt(Vx_o) (so the square root of some unit) and subtracting ((k3/2)*x(i)) (in some unit) I think that this is incorrect as you are subtracting values with different units. You will want to ensure that both have the same units before you subtract one from the other.

Answer 2

[Peter Perkins]

Jocelyn, modulo Geoff's concerns, I think your whole loop can be done as

x = 200*3*(0:5)';
Vx = (sqrt(Vx_o) - ((k3/2).*x))^2;
t = (x./Vx_o).*sqrt(Vx_o./Vx);

and then I guess

t = cumsum(t);

Also, if time should be increasing, that suggests that maybe T should be a timetable rather than a table.