20. (2 points) Fill in the blanks so this program creates two balls. Balll should start at location (50,100) with zero y velocity
and 0.2 x velocity. Ball2 should start at (300,100) with zero y velocity and -0.2 x velocity. The balls should then fall
according to gravity as specified in the Ball class. They should each be 10 pixels in diameter,
Ball balli, bal12;
float gravity = 0.1;
void setup() {
size (400, 400);
balll =
ball2 =
fill (255,0,0);
void draw() {
background (255);
class Ball !
float x, y, xVel, yvel;
int diam;
Ball (float xStart, float ystart, float xv, float yv, int diameter)
x = xStart;
y = yStart;
xVel = xV;
yvel = y;
diam = diameter;
void update() {
// check if hit the ground so need to reverse the velocity
if (y > height-diam/2) {
yvel = -yvel;
// adjust position based on velocity
y = y + yvel;
x = x + xVel;
// adjust the velocity - increasing due to gravity
yvel = yvel + gravity; // always accelerate down
// add some drag
yvel = yvel*0.99;
void draw() {
// draw the ball
ellipse (x, y, diam, diam);
