excessive shaking when applying brakes points to brake rotars being out of round, cracked or warped. have rotors machined
Most common cause is warped rotors.
Stepping on the brakes of a moving car is an example of
Is stepping on the brakes of a car acceleration. That would be deceleration.
YES !
he he he
Check the brakes. You may need new rotors. You didnt say how hard you stand on the brakes because if you are heavy on them it could be the abs unit working properly
warped rotors
Have the front rotors turned on a lathe at a dealership. check brakes and rotors
You probably have rusty/scored brake rotors.
Bad ground in brake light circuit
Sounds like a vacuum leak.
Check the lug nuts