Most times it is because the brake drums or rotor sufaces are warped by overheating and need regrinding to remove the uneven high spots. Also if on an older car they may have been ground so often they are thin and warp easily - and need replacement. High speed and frequent hard braking causes overheating
Yes, it can.
its old or something wrong with the car
Could be in need of a tune up.
No
what chater
wheels need balancing, sometimes shake is only evident at high speed
what shake it up character would definitly perfer to travel by car not airplane
The car breaks (brakes) stop the car.
because if you stop immediately then the car will stall.
yes
check motor mounts
Engine mounts