What causes a truck with all-wheel drive to slip?

The cause of a truck with all-wheel drive slipping is:

1. Cars move forward because the engine's power is transmitted through the tires to the ground, just like how a person uses their feet to run forward;

2. When a car's wheels slip, the friction between the wheels and the ground decreases, and the engine's torque can only reach the tires, not the ground. This causes the wheels to slip, and the car cannot get the push it needs to move forward.

3. Solutions: When a truck slips, you can place branches or rocks under the wheels to increase the friction between the wheels and the ground, so the torque is transmitted to the ground and the wheels no longer slip. This allows the truck to gain power and move forward.