Applying the right kind of force to an object

In my game I am implementing a pinch gesture to move an object closer (pinch close) or push it further away (pinch away). There is one thing to note here and that is that I am applying real world physics to this object, therefore, there should be force applied in order to move this object. The weird thing I am getting is that if do the pinch gesture slowly the object moves just fine, but, if I do the pinch gesture quickly the object doesn't move, or it does but not at the speed at which it should based on the force I'm applying to the screen.

The formula I am using to move the object is rigidbody.addforce(14);

The end result is that it should move at a reasonably natural way.

Can anyone help me figure out why my force is behaving the way it is? Does my force formula need to have another variable that can help me move my object the way it should?