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A search on the topic will turn up many threads.
Also, the lower left of this page has a field "Similar Posts", where a few show up.
For further reading, also have a look at the thread I quoted below. Clicking the little triangel next to my name in the "Quote" box, will take you there 
René Damkot wrote in post #6129113
As can be seen in the images below; The flash will freeze the camera shake / motion blur, provided the subject isn't hit by ambient light.
Last image shows that best: Some parts are sharp, others are hit by light, so are blurred. Other parts still have the background "shining through", since the subject wasn't "covering the background" the whole exposure.
René Damkot wrote in post #5837805
Okay, some images, to cut the slow-chat

One in color:
And one B&W (since that is how they were used in print):
For further reading; here's two threads:One and two (with a few more links in post #2)