import pygame
import sys

# Initialize Pygame
pygame.init()

# Constants
WIDTH, HEIGHT = 800, 600
FPS = 60
GRAVITY = 0.5
BOUNCE = -0.7

# Colors
WHITE = (255, 255, 255)
RED = (255, 0, 0)

# Setup display
screen = pygame.display.set_mode((WIDTH, HEIGHT))
pygame.display.set_caption("Physics Simulation")
clock = pygame.time.Clock()

# Ball properties
ball_radius = 20
ball_x = WIDTH // 2
ball_y = HEIGHT // 2
ball_vel_y = 0

running = True
while running:
    screen.fill(WHITE)

    # Event loop
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

    # Physics update
    ball_vel_y += GRAVITY
    ball_y += ball_vel_y

    # Bounce on bottom
    if ball_y + ball_radius > HEIGHT:
        ball_y = HEIGHT - ball_radius
        ball_vel_y *= BOUNCE

    # Draw ball
    pygame.draw.circle(screen, RED, (int(ball_x), int(ball_y)), ball_radius)

    pygame.display.flip()
    clock.tick(FPS)

pygame.quit()
sys.exit()