Tell me about lenses

I bought a Nikon D7000 with a 35mm stock lenses. My friend had a 55mm 1.8f lenses, which don't zoom, but the focus was awesome and the way the pics came out. I don't know much about lenses, so could you please give me an overview?

I like to take pics for fun.

The D7000 usually comes with an 18-105mm zoom. Apparently you bought the body and lens separately. In my opinion this is usually a mistake for a beginner since a prime lens (non-zoom) can be limiting.

Lens Primer:

On a 35mm film camera or full-frame DSLR (think Nikon D700 or D3 here) a 50mm lens is considered a "normal" lens since its angle of view approximates that of the human eye.

On a 35mm film camera or full-frame DSLR a focal length of between 85mm to 105mm is considered an ideal portrait focal length. On your Nikon D7000 with its 1.5x "crop factor" a 50mm lens will have the angle of view of a 75mm lens on a 35mm film camera or full-frame DSLR. So on your D7000 a 50mm lens makes a good portrait lens.

On a 35mm film camera or full-frame DSLR a 35mm lens is a moderate wide-angle lens. On your D7000 it will have the angle of view of a 52.5mm lens on a 35mm film camera or full-frame DSLR. So on your D7000 the 35mm lens is considered a "normal" lens and will produce pictures close to how you actually saw the scene with your own eyes. The 35mm f1.8 lens is also very useful when shooting in low-light where you don't want to use flash and you want to keep your ISO lower to avoid digital noise.

Any lens you use on your D7000 should have the focal length multiplied by 1.5 to figure the equivalent angle of view of a lens on a 35mm film camera or full-frame DSLR.

For more versatility you might want to consider adding the 18-105mm zoom lens to your kit.