adobe photoshop - How can I represent speed in a graphic?

How can I show speed in this example?

I don't have any vector programs, I'm working in Photoshop.

Any advice will be helpful.

Answer

Create a teardrop shape with the pen tool:

Fill it with white (Command+Delete).

Duplicate, stretch and rotate your copies to match up with some of the lines in the object:

Merge the shapes together by selecting all of them and 1.hit Command+E or 2. right click and choose Merge to Smart Object.

Then add a layer mask and put a slight gradient from the bottom up...