Is the speed limit to prevent hazards caused by inertia? Why?

Note the difference: inertia is a property that an object has when it moves, inertia has no magnitude, but inertia has a force acting on the object, and the magnitude of this force is related to the mass and acceleration of the object.

The purpose of this question is to examine the above knowledge points, which can be guided by a: when people and cars have the same acceleration, or speed movement, the two are relatively stationary, when the brake is suddenly stopped, but the person still has to maintain the original state of motion, so it will lean forward, so for safety reasons, when riding in the car, you should fasten your seat belt.

It can be guided by b: when the initial velocity of the car is too large, when braking in an emergency, it will take a long time to change from the initial velocity to the final speed of 0, and because of the force of inertia, the force that reacts on the person will also be large, for the sake of safety, so the speed limit driving, the relevant formula s=

It can be guided by D: the car is overloaded, then the mass of the object and the car can be regarded as a whole, the mass increases, the force of inertia will increase, in order to be able to brake in time in an emergency, so it must not be overloaded.

It follows that C should be chosen

The faster the speed, the greater the inertia of the object to maintain the speed of motion, the greater the braking distance, and the less easy it is for the car to stop, which is a very dangerous thing on the highway, for example, if the car in front has a problem (breakdown, etc.), the car behind will crash once it can't brake.

Inertia is independent of the magnitude of the speed, so the speed limit on the road is not to prevent inertia. I wonder if you have learned mechanical energy? The greater the speed, the greater the kinetic energy, so the more work the traction does, and the less likely it is to stop.

Forehead... I'll help you ask the teacher tomorrow...

After braking, due to the inertia of the car will slide for a certain distance, the greater the speed of the car, the greater the sliding distance after braking, so it is very unsafe, and the speed limit should be limited.

Inertia is a property of an object that is only related to mass.

The inertia of an object is only related to mass, whereas kinetic energy is related to both velocity and mass.

For motor vehicles, there is a universal (though not strict) rule, that is, the more mass the car, the greater the power. For cars, the mass span will not be very large (except for heavy trucks), and it is generally several times. And the speed is different, from small to large, it can span three orders of magnitude.

And the speed is controllable, and the quality is not something that can be controlled casually.

Of course, the speed limit is due to inertia, f*t=m*v, I believe you know this law. Sometimes it is mistaken to think that it has something to do with kinetic energy, because e=1 2m*v 2 has a certain relationship with the previous formula.

Having said all this, it's up to you to judge right and wrong, because your problem is already a certain problem, so I can only analyze so much. One thing, the speed limit is to be able to brake the car for a certain period of time.

The inertia of an object is only related to the mass of the object!! This must be remembered!

Therefore, the speed limit for motor vehicles only affects its kinetic energy. (Because kinetic energy is related to the mass and velocity of the object, the greater the velocity, the greater the kinetic energy).

The weight limit is because the greater the weight, the greater the inertia, the greater the inertia, the greater the momentum, and the greater the momentum, the greater the damage. The same speed limit is because the higher the speed, the greater the momentum generated by the inertia due to the velocity. That is, the faster the speed, the greater the momentum (not the greater the inertia), and the greater the damage.

In order to reduce the momentum generated by braking, the weight must be limited, and the speed must also be limited.

Weight limits are related to friction. The greater the weight, the greater the friction, the greater the friction, the greater the reaction force generated, and the greater the braking distance.

It's all about inertia.

Because weight and speed are factors that affect inertia in physics, when people reach the end of the run, they have to run a certain distance to stop, and the heavier people need to run a little farther to stop, so the distance is larger. For example, the same road surface at the same speed, the original distance from the car in front of 10 meters, the car weighing 500 kilograms can be stopped as long as it advances 9 meters, and 600 kilograms to advance 11 meters before stopping and hitting.

The speed is the same, just replace the independent variable with speed, the same weight and the same road, and the person with the higher speed should buffer farther. The rest of the ditto, too lazy to fight!

In fact, this question can be understood by transferring him to ordinary running, and empathizing with what you often do in your daily life. If you don't believe it, you can try it yourself.

The dynamic friction factor between the tire and the ground is constant, and the acceleration during braking is certain. Then it can be obtained according to v = 2ax: the braking distance is proportional to the 2nd power of the velocity. For driving safety, reduce the braking distance. Speed limits must be observed.

The weight limit is mainly to consider the damage caused by the pressure of the vehicle on the ground. In order to prolong the service life of the road surface.

Speed limits have nothing to do with inertia.

The weight limit has something to do with friction.