What is traction? Why is it said that traction and resistance are a pair of balance forces when the car is moving in a uniform and straight line?

What is traction? Why is it said that traction and resistance are a pair of balance forces when the car is moving in a uniform and straight line?

Traction is the power of the car. When the car moves in a straight line at a constant speed, the external force on the car is zero, that is, the resultant force of all forces in the direction of the car's movement is zero. In the direction of the car's movement, the car is only subject to traction and resistance, so traction and resistance are a pair of balance forces

What's the meaning of stopping water with the water truck

The water wheel is a noun, the "car" in the water wheel is a verb, and the "car" in the water wheel is the abbreviation of the noun water wheel

1. Make a cylindrical bucket without cover, the circumference of the bottom is 6.28 decimeters, the height is 6 decimeters, at least use iron sheet () square decimeters to hold water () liter
2. If the height of a 20 cm cylinder increases by 1 cm, its surface area will increase by 12.56 square cm. The original volume of this cylinder is () cubic cm
3. Mischievous bought a toothpaste with a net content of 56.52 cubic centimeter. The inner diameter of the circular exit of the toothpaste is 6 mm. Mischievous brushes his teeth every morning and evening. The toothpaste extruded each time is about 2 cm long. It is estimated that this toothpaste can last () days
This problem should not be difficult

1. To make a cylindrical bucket without cover, the circumference of the bottom surface is 6.28 decimeters, and the height is 6 decimeters. At least the iron sheet (40.82) square decimeters should be used to hold (18.84) liters of water. 2. If the height of a cylinder is increased by 1 cm, its surface area will be increased by 12.56 square centimeters