I notice when I stop in a car, the front dips down. It's not just my car, it's all vehicles with brakes. What are the physics behind this frontal dip?
2007-06-16 20:37:28 · 8 answers · asked by Ian 2 in Science & Mathematics ➔ Physics
The force of the wheels against the bulk of the car results not only in the linear force responsible for the slowing of the car, but also a torque, since the direction of this force is not colinear with the center of mass of the vehicle. In other words, if you have a pencil lying flat on your desk, you can push it forward at any point, but unless that point is the dead center, in addition to moving it forward, you also get a rotation. The same is true when the brakes are put on. Think about a really fast acceleration . . . now the effect is in the opposite direction, and reversing the rotation LIFTS the front end of the vehicle (good for wheelies).
2007-06-16 20:53:49 · answer #1 · answered by supastremph 6 · 0⤊ 1⤋
Your car is a massive body in motion, so even after the power to the engine stops, the car's mass stays in motion. When you apply the brakes, the brakes act directly on the wheels, which work to stop the wheels from turning.
The wheels are attached to the rest of the car by means of a flexible suspension system, and the engine, the most massive part of the car, is attached to the frame by a flexible system as well. When the wheels top turning, the body still has forward momentum, so it keeps going forward, but is limited by the suspension system. Likewise, the engine still wants to go forward when the body stops until it is limited by its mounts.
Because of the position of of the engine and the arrangement of the various connections, the forward motion is converted into the dipping motion you experience.
The return to the "default" position of the vehicle is called "chassis set".
2007-06-16 20:49:50 · answer #2 · answered by Anonymous · 3⤊ 1⤋
For every action is an opposite reaction.
The force you exert when stopping the car like when braking, is opposed by an equal force that makes your car move a little forward. This is when the vehicle as you say dips down.
In short, momentum.
2007-06-16 21:00:32 · answer #3 · answered by russ law 2 · 0⤊ 1⤋
Eight previous replies and only one reference to the key concept of torque! supastremph is correct. It's very hard for people to sort through so much rubbish, so I thought I'd reinforce it.
Whenever the line in the direction of the force vector, drawn from point of application to a rigid body does not pass through the center of mass, a torque is applied to the body, causing it to rotate. The friction of the tire on the road is directed horizontally rearward, missing the COM (which is well above the road). The rotation only stops when shock springs are sufficiently compressed in the front and stretched in the rear to provide in an opposing counter-torque of equal magnitude.
2007-06-17 04:49:27 · answer #4 · answered by Dr. R 7 · 0⤊ 0⤋
When you brake a car, you abruptly stop its motion and due to its inertia it actually tries to continue its linear motion which it cannot. Instead a torque (couple) due to the frictional force and the force responsible for its motion acts on it, causing the rotational motion. i.e.back of the car is lifted up and the front dips.
2007-06-16 20:49:15 · answer #5 · answered by Ayatollah 2 · 1⤊ 1⤋
Because of the force exerting on the car exerted on the front of car due to brake and the car become depend
2007-06-16 21:04:50 · answer #6 · answered by Anonymous · 0⤊ 1⤋
when u brake all the mass of the car is trasnfered infront so with this extra momentum ur car dips forward
2007-06-16 21:13:42 · answer #7 · answered by vignes 3 · 0⤊ 1⤋
The momentum of the car is pushing against the resistance of the brakes.
2007-06-16 20:41:24 · answer #8 · answered by Koosher 5 · 0⤊ 2⤋