1996 Chevy Tahoe knocking noise

Everytime I accelerate from a stopping point, I hear a knock you can feel. It sounds like it is coming from the drive shaft but I am not sure. Another problem is whenever I am coming to a stop, the steering wheel shakes alot and it feels as if the brake rotors are messed up. I had a friend tell me that it may be the u joint, but we are not sure. Any suggestions are welcome. Thanks