2006-07-17 04:38:59 · 14 answers · asked by BUNTY 1 in Science & Mathematics ➔ Physics
The car moves because the wheels rotate. The brakes are an external force acting on the rotation of the wheels.
2006-07-17 04:42:01 · answer #1 · answered by Michael F 5 · 0⤊ 0⤋
In reality, the only forces acting upon a car while it is driving are the frictional forces create by the road and air, and the rotational forces actiong in the tires. When a car breaks, an additional force is applied to the tires through the break pads. If this were an internal force, it would have no effect on the speed of the car. Instead all the forces leading to the application of the break are internal; the force is translated from internal to external once the pads come into contact with the tires.
Newton's laws are not incomplete as a previous answer states. Friction is a force, and therefore falls under the F=ma relationship.
2006-07-17 11:46:26 · answer #2 · answered by MandyT 2 · 0⤊ 0⤋
With out an external force, car cannot be stopped.
By applying the break, the rotation of the wheels alone is stopped. That means the car is not stooped by applying break.
As far as the rotation of the wheels is concerned, the break is external to the wheel and hence its rotation is stopped.
Having the wheel’s rotation is stopped, the car still moves on the road and “its speed is not reduced”; but now it slides on the road.
This sliding introduces friction between the tyres and road which is external force.
The car is stopped.
Have you ever thought of ‘how a car moves on the road with out applying a force externally’?
2006-07-17 11:57:04 · answer #3 · answered by Pearlsawme 7 · 0⤊ 0⤋
You do have an interesting point about the statement of Newton law. If a force is what it alludes to than you have to find a force to stop the car.
However it is impossible to find a single force since forces only exist in pairs
There is a problem in stopping a Car as per the above statement of Newton's Law..
A car mechanic rather then a physisit may be the more appropriate person to advise on this problem.
2006-07-17 11:54:31 · answer #4 · answered by goring 6 · 0⤊ 0⤋
An external force is acting on it. Your brake pads are external to the wheels and they act on the wheels to stop them. The wheels are external to the car and when they stop they cause the car to stop.
Besides, friction is an external source and you are applying friction to stop the car. In addition to the friction of the brakes, you have the friction of the road which is really what stops the car, because you there was no friction on the road you could stop the wheels all you want and the car would keep on moving.
2006-07-17 11:44:18 · answer #5 · answered by Icy U 5 · 0⤊ 0⤋
What EXACTLY stops the car when the brakes are applied?
The friction between the tires and the road surface. This is the external force that stops the car, not the application of the brakes.
2006-07-17 13:16:25 · answer #6 · answered by flandargo 5 · 0⤊ 0⤋
Stopping the car externally would be for example hitting a tree. Not a good method.
A car's brakes however dampen the chain of mechanical energy that is propelling the car.
2006-07-17 11:42:37 · answer #7 · answered by Anonymous · 0⤊ 0⤋
the brake is external to the wheel... the wheel is in motion but the break is stationary within the vehicle itself... you are stopping the wheel from turning you arent stopping the car from moving... the car stops because it is connected to the wheel... if that were the case... the brake would push against the ground like a foot and stop it that way
2006-07-17 11:43:51 · answer #8 · answered by Grin Reeper 5 · 0⤊ 0⤋
The inner parts too depends on external factors such as air ,gravity....So if u break the car under zero gravity ,it will still move in that direction .But ,ur question is somewhat good to think.==Byeeeeeee
2006-07-17 11:43:25 · answer #9 · answered by MaxMetallica 3 · 0⤊ 0⤋
Breaks are still considered external force ..
2006-07-17 11:42:00 · answer #10 · answered by AST 2 · 0⤊ 0⤋