What would cause to shake or vibrate when you hit break hard?

What would cause a 2001 Chevrolet cavalier
to vibrate bad when hit break for sudden
stop you can feel it literally shaking when hit
break or when go to stop have to have extra
time to stop so stop you right sometimes
sounds like hear either grinding noise or
roaring noise also just started this today
landlord put new gravels down in our mobile
home park when go pull out it just want to
spin not pull out but once got out gravels it
did ok and last week my husband change
back break shoes it was getting either break
caliber or break one hot u could smell them
burning he was having trouble getting back
break shoes adjuster on right but he said
finally got them on but every once I. While
like when take to store which 10 minutes
from me you can smell something burning
what could be my problems