Faking real world motion

We are going to create the effect of an object swinging through the air. This raises a couple of challenges, The object will be rotated from one end rather than the center and we want to create the illusion of the object slowing down. No problem Lets do it! Begin with an object that is separated from its background. There are plenty of tutorials that show you how to do that. Place the object on its own layer.

Duplicated the layer and choose the bottom object layer.

We are going to create the motion effect on the layer.
Choose Filters>Blur>Radial Blur
Click and drag on the preview window and move the center of rotation to the desired pivot point of the image as indicated.
Set the amount to 6

Click ok and you will now see a little bit of a movement effect. We still have a lot of work to do.

Duplicate the blurred layer and once again choose the bottom object layer (layer 1)

Apply the blur again this time make it 30 pixels. (Note that Photoshop will have remembered the previous center of rotation)

At the moment it looks like the object is swinging back and forth like a turbo charged pendulum or a metronome. We want it to look like it is moving in a single direction.

Press Cmd+t (Ctrl+T pc) This will evoke Free Transform.
Click on the center point and move drag it to the pivot point as shown

Move the mouse outside one of the corners until it turns into a curved arrow, Click and drag to rotate the blur. Notice it rotates from the new pivot point. (Pretty cool aye? *My Dave Cross impersonation*)

Choose the other blurred layer and repeat the roatation

Fiddle with the transparencies of the blurred layers until you happy with the result.
There you have it. Simulated motion in Photoshop

I hope this fun for you and that you find it useful in the future. (Faked swinging cats etc; they really are nice creatures, so just fake it and don't actually swing the poor felines).