There could be a problem, and it could be also nothing to worry about. Best bet is to have your mechanic check it out.
Brake pads worn or dirt lodged in brake pad
Loose or worn belt?
the force of something braking
Drum & Disc are the two types of braking systems on a car.
braking
it will temporarily make it not squeek but can make it slip
Assuming you mean "braking", aggressive braking.
Try to reduce speed through engine braking. Try the parking brake. Aim for something cheap and soft,
ABS??
Hydraulics.
The braking system makes a car stop.
Assuming that braking force is the friction force; F=m*a 4000 = 1000*a a = 4 m/s^2