I'm creating a sketch for class that will eventually let the user hit a golf ball in an attempt to make it into a hole. The ball will be affected by the friction caused by the ground, wind speed and direction, and intermittent obstacles. The code is still very primitive however, as about 90% of the time when the ball hits the ground it then vibrates erratically and slowly sinks into the ground. I assume this is being caused by the ball dropping slightly below the restricted area (385 pixels) and being reflected up and down instantaneously because it remains below said area.

I searched through the forums for other newbies trying to solve their bouncing ball issues, and the only one I could find contained a solution that resulted in the same issue.  Any help is appreciated. Code to follow:

1. float ballX = 100.;
   
2. float ballY = 385.;
   
3. float gravity = .4;
   
4. float ballSpeedX = 10.;
   
5. float ballSpeedY = random(-15., -5.8);
   
6. float windSpeed = random(-.5, .5);
   
7. Cloud c1 = new Cloud(random(100, 1400), random(250), windSpeed);
   
8. Cloud c2 = new Cloud(random(100, 1400), random(250), windSpeed);
   
9. Cloud c3 = new Cloud(random(100, 1400), random(250), windSpeed);
   
10. Cloud c4 = new Cloud(random(100, 1400), random(250), windSpeed);
    
11. Cloud c5 = new Cloud(random(100, 1400), random(250), windSpeed);
    
12. 
    
13. 
    
14. void setup() {
    
15.   size(1500, 400);
    
16.   smooth();
    
17.   noStroke();
    
18. }
    
19. 
    
20. void draw() {
    
21.   background(140, 200, 210);
    
22.   fill(100, 150, 50);
    
23.   rect(0, 390, width, height);
    
24.   fill(255, 0, 0, 200);
    
25.   triangle(1400, 340, 1400, 360, 1425, 350);
    
26.   strokeWeight(3);
    
27.   stroke(0);
    
28.   line(1400, 340, 1400, 390);
    
29.   noStroke();
    
30.   fill(0, 0, 0, 200);
    
31.   rect(1393, 390, 14, 10);
    
32.   fill(255, 255, 255, 255);
    
33.   c1.update();
    
34.   c2.update(); 
    
35.   c3.update();
    
36.   c4.update();
    
37.   c5.update();
    
38. 
    
39. 
    
40.   ellipse(ballX, ballY, 8, 8);
    
41. 
    
42.   ballX = ballX + ballSpeedX;
    
43.   ballY = ballY + ballSpeedY;
    
44.   ballSpeedY = ballSpeedY;
    
45. 
    
46.   if (ballX >= width) {
    
47.     ballSpeedX = ballSpeedX * -1.;
    
48.   }
    
49. 
    
50.   if (ballX <= 0) {
    
51.     ballSpeedX = ballSpeedX * -1.;
    
52.   }
    
53.  
    
54. 
    
55.   //FRICTION
    
56.   if (ballY >= 385) {
    
57.     ballSpeedY = ballSpeedY * -.5;
    
58.     ballSpeedX = ballSpeedX * .5;
    
59.   }
    
60. 
    
61.   //GRAVITY
    
62.   ballSpeedY += gravity;
    
63. }