Why can people push the cart when they are in the car?

First of all, consider people and cars as a system.

When a person pushes the ground, such as pushing it backwards, it is actually the system of S exerting a force f on the ground.

Because there is friction, then when a person pushes the ground, the ground also has a reverse force -f towards the system S, and a negative sign indicates that the force is opposite.

Then the system is subjected to the force of -f, and it will naturally move.

In fact, when you use very little force, the car will not move, and the friction at this time is called static friction.

Slowly increase the strength, at a certain time the car will move, that is, this force is greater than the maximum static friction, and then the car moves, and the relative friction is called dynamic friction.

In fact, it is also the knowledge of action and reaction force.

Supplement the knowledge points:

Force is the action of an object on an object, so the forces all come in pairs. There is force and force. The force generated by the interaction between two objects through different forms, such as attraction, relative motion, deformation, etc., is called the force.

Since the interaction between two objects is always reciprocal, then we call the pair of forces that interact between objects the action force and the reaction force. Where there is an action, there is a reaction. We can call any one of these forces an action force and the other a reaction force.

Action and reaction force, when people exert force on the ground, that is, the whole of people and vehicles exert force on the ground, when this force is greater than the friction force of the ground, the whole of people and vehicles can move.

What's the question? Brain teasers?

What car? Car, bicycle or trolley? The situation is different.

If it's a brain teaser, the answer is: the person in the cart and the person pushing the cart are not the same person.

If it is a trolley, the answer may be: a person stands on the cart, and the two sides of the cart are pushed, and the cart can move.

That car is a wheelchair, haha.

The reason why people stand on the car and move with the car is because the car will produce a frictional force on the soles of people's feet, and this force makes people move; If you sit on a chair, it is the push of the chair against the person's back that makes the person move.

The car has a forward friction force towards the person, so the person will move forward with the car.

The car turns around, so people follow suit.

Due to inertia, the car is moving, and the person is stationary.

It should be that the controller of the car is broken, and it costs more than 100 yuan to replace it.

If the battery is low, or the starter is not working properly. The wheels are rotated by means of human pushing. The person sitting in the car hits the key to the ON gear, and when the car runs fast, the gearbox at this time transmits the torque to the clutch, and the torque is transmitted to the engine through the clutch, driving the engine to run, and the gearbox is equivalent to acting as a starter and starting the engine.

So the engine was able to ignite.

The battery is running out of power. You can't get a car with a motor. The wheels are rotated by means of human pushing. The occupants of the car open the electric door, and when the car moves faster, the gearbox acts as a motor to start the engine.

It's faulty. Generally, the battery is out of power, or the starter is faulty.

The car needs to be pushed when the battery is out of power. And it must be a manual transmission car, and the vehicle should not have other problems.

The battery is out of power and needs someone to help or it is raining and there is water!

A gasoline car can't push a diesel car.

Hello, it doesn't matter, a lot of cars need to be pushed when there is a problem, and the vertical auspicious preparation is destroyed like that. [If you have a problem with the car, ask the car master.] Professional technician of 4S shop, the banquet stall will be solved in 10 minutes. 】

Hello is no harm [There is a problem with the car, ask the car master. 4S shop professional technician, 10 minutes to solve. 】

There is no hazard if it is in neutral and the handbrake is not pulled, and there is wear on the brake pads if the handbrake is not released.

Hello car owner, the car can still be parked and push the script Yuming handbrake has a problem, you have to check it as soon as possible [There is a problem with the car, ask the key to the rock car master. The professional technician of the 4S shop will be solved in 10 minutes. 】

Of course, you can't push it. When a person pushes a cart, the cart also gives a reaction force to people. An action force is a set of forces that are opposite in direction and of the same magnitude.

As a result, if you cancel each other out, and see the person and the car as a whole, the resultant force is 0. So you can't push it.

Whoever analyzes this for you is the second fool.

I like to be the first to get on the bus at lightning speed, or the last to get on the car at turtle speed, in short, relief.

During the rush hour, I stop the bus, don't sit, don't sit if you have a seat, troublesome, see the elderly to give up the position, it's better to stand and worry