Make an array from function input and output
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I have a function that inputs velocity and angle, and outputs the distance the ball travels. Function below:
function distance = DTask1_f (v, angle)
h = 1.5;
g = 9.8;
t = linspace (0,10,1000);
x=v*cos(angle*pi/180)*t;
y=h+v*sin(angle*pi/180)*t-0.5*g*t.^2;
ind = find (x == min(x(y<0)));
fprintf ('The ball hits the ground at a distance of %5.4f meters.', x(ind));
distance = x(ind);
end
I now need to write a script that uses the function, and while using a set value for velocity, will graph angle and distance over a set of angles. My script so far:
for angle = 10:13
v = 4;
y = DTask1_f (v, angle);
x = [angle];
a = [x;y]
end
figure
plot(x,y)
xlabel('Angle (deg)');
ylabel('Distance (m)');
title('Ball Trajectory');
I think I need to first make an array using the angle (input) and distance (output), and then graph the array, but im not sure how to make the array. At the moment, it only gives me the last two points.
Apologies if this is a simplistic question, but thanks for the help.
采纳的回答
Hi,
use:
angle_range = 10:1:13
for k = 1:length(angle_range)
v = 4;
a(k,2) = DTask1_f (v, angle_range(k))
a(k,1) = angle_range(k)
end
figure
plot(a(:,1),a(:,2))
xlabel('Angle (deg)');
ylabel('Distance (m)');
title('Ball Trajectory');
If you want to extend or vary the range of angle or make other stepsize for angle modify first line.
Best regards
Stephan
3 个评论
Corey Kovacs
2018-9-2
Hi,
this part has a dynamic legend now for v - No need to write it by hand everytime it is changed:
angle = 0:60;
for k = 1:length(angle)
v = 60;
a(k,2) = DTask1_f (v, angle(k));
a(k,1) = angle(k);
end
figure
plot(a(:,1),a(:,2))
xlabel('Angle (deg)');
ylabel('Distance (m)');
legend(['v = ', num2str(v), ' m/s'])
title('Ball Trajectory');
The function should now work as you wanted it to do, with some more informations when fprinf command gives output:
function distance = DTask1_f (v, angle)
h = 1.5;
g = 9.81;
t = linspace (0,15,50000);
x=v*cos(angle*pi/180)*t;
y=h+v*sin(angle*pi/180)*t-0.5*g*t.^2;
ind = find (x == min(x(y<0)));
distance = x(ind);
if t(ind) <= 10
fprintf ('Angle: %1.0f Degrees - The ball hits the ground at a distance of %5.4f meters in %5.4f seconds. \n',angle, x(ind), t(ind));
else
fprintf ('NaN - Angle: %1.0f Degrees - Time: %5.4f seconds \n', angle, t(ind));
end
end
Best regards
Stephan
Corey Kovacs
2018-9-3
更多回答（1 个）
KSSV
2018-9-1
angle = 10:13 ;
x = angle ;
y = zeros(size(angle)) ;
for i = 1:length(angle)
v = 4;
y(i) = DTask1_f (v, angle(i));
end
figure
plot(x,y)
xlabel('Angle (deg)');
ylabel('Distance (m)');
title('Ball Trajectory');
3 个评论
Corey Kovacs
2018-9-2
Zach Russell
2023-10-12
5 years later...I found this answer to be easier to follow. Thanks for the help, if you are still out there.
KSSV
2023-10-12
@Zach Russell yes I am here... :) you can acknowledge by voting the answer.
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