You could apply a small force opposite the direction the ball is moving. Here a function is called ten times, the first nine times getting the velocity of the ball and applying a small force opposite to it. On the tenth time the ball is stopped completely.
Code:
import viz
viz.go()
viz.phys.enable()
ground = viz.add('tut_ground.wrl')
ground.collidePlane()
ball = viz.add('ball.wrl', pos = [0,1,8])
ball.collideSphere()
ball.applyForce([2,0,10], .1)
num = 1
def slowBall():
global num
#slow down the ball
if num <10:
vx,vy,vz = ball.getVelocity()
ball.applyForce([-vx,-vy,-vz], .01)
num+=1
#stop the ball
else:
ball.setVelocity([0,0,0])
ball.setAngularVelocity([0,0,0])
#call function 10 times
vizact.ontimer2(.3,9, slowBall)