Pull and release ball

from random import randint, uniform
import time
import pygame
from pygame import Rect as R
from pygame import Vector2 as V
from pygame.locals import *

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

pygame.init()
PDS = pygame.display.set_mode()
PDR = PDS.get_rect()
FPS = 120

ball = V(PDR.center)
rad = 80
v = V()
f = V()

pressed = False

dts = time.time()
while True:
    pygame.event.get()

    now = time.time()
    dt = (now - dts) * FPS
    dts = now

    mp = V(pygame.mouse.get_pos())
    dist = mp.distance_to(ball)

    mb = pygame.mouse.get_pressed()
    if mb[0] and not pressed:
        if dist <= rad:
            pressed = True
    if pressed:
        if not mb[0] and dist > rad:
            deg = V().angle_to(mp - ball)
            a = V(1, 0)
            b = a.rotate(deg + 180) * (dist - rad)
            v = b / 10

            pressed = False

    ball += v * dt
    if v.x != 0 or v.y != 0:
        a = v.normalize()
        v -= (a / 10) * dt
    if ball.x + rad > PDR.w:
        ball.x = PDR.w - rad
        v.x = -v.x
    if ball.x - rad < 0:
        ball.x = rad
        v.x = -v.x
    if ball.y + rad > PDR.h:
        ball.y = PDR.h - rad
        v.y = -v.y
    if ball.y - rad < 0:
        ball.y = rad
        v.y = -v.y

    PDS.fill(0)
    if pressed and dist > rad:
        pygame.draw.line(PDS, RED, ball, mp)
    pygame.draw.circle(PDS, WHITE, ball, rad)

    pygame.display.update()