what is causing my car to jerk when i hit the brakes
Yes, you have a problem with the front brakes. If it's a shaking or a pulsation when applying the brakes, then there is a problem with the rotors and most likely will have to be replaced. If your getting a pullung or jumping to one side when braking, that would indicate a problem with the calipers or front brake hoses. The calipers bind and the hoses deteriorate internally and get restricted. Definately have it inspected by a reputable shop to be safe,