Af-s lens for nikon d3100?

If I buy the 50mm 1.8G tht is af-s and have a built in autofocus motor! So can I shoot videos without continuous auto focus on d3100?
How can I make it look like my bros 550D? Will the lens do it?

The new 50mm f1.8 AF-S has a motor and will autofocus on your d3100

If you do not want auto-focus, you can turn it off and manually focus any Nikon lens

If a lens has "G", like f/1.8G, auto focus will work at photography and videos, so don't worry.
Make it look like your bros 550D? What? The lens or camera? All cameras are so similar you can't really tell a difference between two.
Here's a Lens Buying Guide - http://www.the-dslr-photographer.com/2009/11/buying-a-lens/
- Nikon D3100 Lens Upgrade - Tamron SP 70-300mm f/4-5.6 Di VC USD Lens (A005, Nikon Mount)?
- Can this: NIKON AF 75-240MM 1:4.5-5.6 D ZOOM LENS type of lens be used on a Nikon D3100?
- Nikon D3100. Will a 52mm lens cap fit my lens?
- Nikon d3100 and Nikon 50mm f/1.8D AF Nikkor Lens for Nikon Digital SLR Cameras?
- Nikon d3100 and Nikon 50mm f/1.8D AF Nikkor Lens for Nikon Digital SLR Cameras? - 1