Why does your car shake when you accelerate?

Why does your car shake when you accelerate?
You first have to make sure if the shaking is occurring only with the vehicle itself or with the brakes or gas pedal. It could be various reason. I can only help by sharing what I know from my experience I had recently.

I recently had some car issues with my 94 Accord. Whenever I acclerated between 60-73 mph my gas pedal and car would shake. This even occured when I Brake my car within that speed zone as well. The shaking that occured while I was braking was due to my front rotors. It simply needed to be changed. I asked a second mechanic for his opinion. (I didn't trust the guy at Brake Master. I came out with more problems for my car after the free brake check) While my car was jack up ( I was present under my car) the mechanic showed me that my axis (or was it my axel) was loose. He tugged on it and it moved. The bearings was cracked as well. Since this part of my vehicle was not stable, my car shakes when I accelerate. I am not a mechanic so please correct me if I am wrong. God Speed on finding the actual problem. Sometimes the best thing to do is go to a trustworthy mechanic and get it checked up.