Bouncing Ball Animation Getframe

I don't understand what I am doing wrong. I have to create an animation of a ball bouncing. But I have to repeat a for loop for each bounce. It also plays the animation twice. Is there a simpler way of doing this? Also, is there a way to speed up the code so that the animation does not play so slowly? I was thinking that I could write a function that would call it to repeat the animation but I am not sure.

%%Animation 

clc, clf, clear

g = 9.81; 
theta0 = 45*pi/180; 
v0=5; 
t(1) = 0; x = 0; y = 0; 

plot(x,y, 'o', 'MarkerFaceColor','b', 'MarkerSize', 8)
axis([0 8 0 .8]); 
dt = 1/128;
M(1) = getframe
for j = 2:100
    t(j) = t(j - 1) + dt; 
    x = v0*cos(theta0)*t(j); 
    y = v0*sin(theta0) * t(j) - 0.5*g*t(j)^2; 
    plot(x,y, 'o', 'MarkerFaceColor', 'b','markerSize', 8);
    axis([0 8 0 .8]);
    M(j)= getframe; 
     
end
M(2) = getframe
t(100) = 0;
v0 = v0*.8;
for j = 101:198
    t(j) = t(j - 1) + dt; 
    x = v0*cos(theta0)*t(j)+2.5; 
    y = v0*sin(theta0) * t(j) - 0.5*g*t(j)^2; 
    plot(x,y, 'o', 'MarkerFaceColor', 'b','markerSize', 8);
    axis([0 8 0 .8]);
    M(j)= getframe; 
    
end 
M(3) = getframe
v0 = v0*.8;
t(198) = 0; 
for j = 199:300
    t(j) = t(j - 1) + dt; 
    x = v0*cos(theta0)*t(j)+4; 
    y = v0*sin(theta0) * t(j) - 0.5*g*t(j)^2; 
    plot(x,y, 'o', 'MarkerFaceColor', 'b','markerSize', 8);
    axis([0 8 0 .8]);
    M(j)= getframe; 
    
end 

M(4) = getframe
v0 = v0*.8;
t(300) = 0; 

for j = 199:300
    t(j) = t(j - 1) + dt; 
    x = v0*cos(theta0)*t(j)+4; 
    y = v0*sin(theta0) * t(j) - 0.5*g*t(j)^2; 
    plot(x,y, 'o', 'MarkerFaceColor', 'b','markerSize', 8);
    axis([0 8 0 .8]);
    M(j)= getframe; 
    
end 
movie(M, 1, 1000)

Answer 1

[Alan Stevens]

Like this?

g = 9.81; 
theta0 = 45*pi/180; 
v0=5; 
dt = 1/128;
ntimes = 400;
tend = ntimes*dt;
t = linspace(0,tend,ntimes);
vx = v0*cos(theta0);
vy = v0*sin(theta0);
x = 0; y = 0; 
xmax = vx*tend;
plot(x,y, 'o', 'MarkerFaceColor','b', 'MarkerSize', 8)
axis([0 xmax 0 .8]); 
M(1) = getframe;
treset = 0;

for i = 1:ntimes
    
    x = vx*t(i);
    tm = t(i) - treset;
    y = vy * tm - 0.5*g*tm^2; 
    plot(x,y, 'o', 'MarkerFaceColor', 'b','markerSize', 8);
    axis([0 xmax 0 .8]);
    M(i)= getframe; 
    if y<0
        y = 0;
        vy = 0.8*vy;
        treset = t(i);
    end
      
end
close
pause(1)
movie(M, 1, 50)

[Gabrielle Bartolome]

Why did you set ntimes = 400? Is that a random number you chose to get the for loop to iterate??

[Alan Stevens]

Yes, just a random number!

[Gabrielle Bartolome]

What does tend represent? Is that when y = 0? or when it hits the ground?

[Alan Stevens]

It's just the total time. Just change the number of steps to change the total time.

Answer 2

[Image Analyst]

See my attached demo for creating an animation from figures. You can set the frame rate for the VideoWriter.