adding inertia to a UIPanGestureRecognizer

I am trying to move a sub view across the screen which works, but i also want to add inertia or momentum to the object.
My UIPanGestureRecognizer code that i already have is below.

Thanks in advance.

UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self       action:@selector(handlePan:)];
[self addGestureRecognizer:panGesture];

(void)handlePan:(UIPanGestureRecognizer *)recognizer
{

    CGPoint translation = [recognizer translationInView:self.superview];
    recognizer.view.center = CGPointMake(recognizer.view.center.x + translation.x,
                                     recognizer.view.center.y + translation.y);
    [recognizer setTranslation:CGPointMake(0, 0) inView:self.superview];

    if (recognizer.state == UIGestureRecognizerStateEnded) {
        [self.delegate card:self.tag movedTo:self.frame.origin];
    }
}

Again thanks.

Have a look at RotationWheelAndDecelerationBehaviour. there is an example for how to do the deceleration for both linear panning and rotational movement. Trick is to see what is the velocity when user ends the touch and continue in that direction with a small deceleration.