have your brakes checked
When a car squeals while moving, but the brakes still work properly, it could be a squeal from a drive belt. It could also mean that something like a tire rim is rubbing on the brake rotor. A vacuum leak in a small hose under the hood will also cause a squealing noise.
It is the law of inertia bringing you forward while the car stops, the law of inertia states that an object at rest tends to stay at rest, while an object in motion tends to stay in motion.
I'd have those looked at while your car still stops
Check that the fan belt is tight.
something is obviously touching rotor when you brake. Take wheel off and check by spinning rotor.
Check your brakes and CV joints
the answer is A= 69.6 km/h
Because a body in motion tends to stay in motion. See the link, The Car and The Wall.
There may be damage or misalignment in the front brakes if this is where the sound is coming from. If it is from more generally under the hood, this can be the power steering.
Putting the throttle or gearshift in reverse thrust.
break away brakes in case you lose trailer while in motion
Check to see if engine is getting fuel and spark