When someone pushes a car with a weight of 500 cattle and advances at a constant speed of 10 meters on the uneven horizontal ground, what work does he do A 5 * 10 cubic coke B 500 joules C 0 coke D condition is not enough to calculate

When someone pushes a car with a weight of 500 cattle and advances at a constant speed of 10 meters on the uneven horizontal ground, what work does he do A 5 * 10 cubic coke B 500 joules C 0 coke D condition is not enough to calculate

If we advance 10 meters at a constant speed on an unsmooth horizontal plane, the work done should be w = f · s, while the friction force F = friction coefficient * g. there is no explanation of friction coefficient in the title, so the condition D is insufficient

There are 80 cattle and 120 sheep on the grassland. How many times is the number of cattle? How many times is the number of sheep?

The head number of cattle is 80 / 120 of that of sheep = 2 / 3
The head number of sheep is 120 △ 80 = 1.5 times that of cattle

Press the object with a gravity of 50 N on the vertical wall with a horizontal force of F = 80 n, but the object just slides along the wall at a constant speed,
What's the friction? What's the direction?

The friction force in the vertical direction is the same as gravity, so the friction force in the 50N direction is upward

Xiaoming pushes the cart forward at a constant speed with 10N thrust. When he sees a child in front of him, he immediately uses 6N force to pull the cart, but the cart is still moving forward. Xiaoming applies a backward pull on the cart, which changes the direction of the cart. The friction force on the cart is 10N, and the combined force on the cart is 16N
Please draw the diagram of output according to the title
2. Why does Xiao Ming switch to 6N lira cart immediately, and the car is still moving forward?
3. How is the resultant force of shopping cart 16N obtained?

1, slightly 2. The speed direction is opposite to the force, and the object decelerates. 3. The dynamic friction is always opposite to the direction of motion, the same direction as the tension, and opposite to the direction of motion! 10 + 6 = 16N