There is a 100N object on the rough horizontal ground, which moves forward at a constant speed of 10m in 10s with 20n horizontal tension A. The power of gravity is 100wb. The power of supporting force is 100wc. The power of pulling force is 200wd. The power of pulling force is 20W
The direction of gravity is vertical downward, the object moves horizontally, there is no moving distance in the direction of gravity, so gravity does not work, the power of gravity is 0, so a is wrong; the direction of supporting force is vertical upward, the object moves horizontally, there is no moving distance in the direction of supporting force, so the supporting force does not work, the power of supporting force is 0
RELATED INFORMATIONS
- 1. Under the action of horizontal tension f = 100N, the object with weight g = 500N slides along the horizontal ground at a uniform speed 1. If the horizontal pulling force is suddenly removed, find the sliding friction F when the pulling force is removed 2. If the gravity of the object is increased by 100N, in order to keep the object moving in a uniform and straight line, what is the horizontal tension f '?
- 2. A 500N object is still on the horizontal ground, and the pressure on the ground is 0______ N. If the object is subjected to 100N vertical upward tension, the pressure on the ground is______ N. If the object is placed on an inclined plane, the pressure on the inclined plane will decrease______ 500N (fill in "greater than", "equal to" or "less than")
- 3. Shanghai Grade 8 Volume 2 physics knowledge points The first chapter is machinery and work The second chapter is heat and energy Just these two chapters The trial edition of Education Press
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- 5. How to do the second sub question of question 9 on page 89 of the mathematics book of the sixth grade volume I of the people's education press?
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- 7. What is exercise 1 in mathematics book p16-17 3. As shown in the figure, Xiaohong wants to measure the height of the big tree 30m away from A. she stands at a and looks up at the top of the tree B, with an elevation of 30 ° (i.e. ∠ BDE = 30 °). Given that Xiaohong is 1.52m tall, she can calculate the height of the big tree (the result is accurate to 0.1M)
- 8. There are a group of chickens and rabbits. The total number of legs is more than twice the total number of heads. How many rabbits are there?
- 9. How to answer the second question on page 59 of mathematics in grade 4 of primary school
- 10. My height is 1.56cm, weight 58kg is very fat? How many jin do I need to lose
- 11. Xiao Zhang uses a horizontal pull force of 30n to lift an object with a weight of 100N and make it move 5m horizontally. After that, the pull force does work J and the gravity does work J The explanation of gravity work,
- 12. When an object weighing 100N is pulled horizontally to the right by 20n and moves horizontally to the right at a constant speed for 5m, the work done by the pulling force is______ J. What does gravity do______ J. What is the resistance to an object______ N. Direction______ .
- 13. If someone pulls a 100N object forward 5m on the horizontal ground with a 50N horizontal pulling force, the work done by the pulling force on the object is () the work done by gravity on the object ( Big brothers and sisters, help to solve this problem
- 14. When an object moves eastward at a speed of 5 m / s for 6 m / s, and northward at a speed of 3 M / s for 4 S, the velocity of the object in the 10 s is the same What is the average speed.
- 15. The pulley block is used to pull the object a on the horizontal ground to move forward at a uniform speed of 5m within 10s. If the weight of the object is 10000n, the friction between the object and the ground is 200N, the mechanical efficiency of the pulley block is 80%, and the friction of the machine itself is not taken into account. To find out (1) how much work is done by the pulling force? How much extra work is done? (2) how much is the pulling force F? (3) how much is the pulling force power?
- 16. A wooden box is placed on the horizontal ground. The gravity of the box is 4000N. Under the horizontal thrust of 2000N, the box moves forward at a speed of 0.5mgs for 10s (1) How far does the box go? (2) What is the work done by the thrust on the box in these 10 seconds?
- 17. Why is it that when the rope is stretched straight and breaks suddenly, the tension of the rope will disappear instantly, while when both sides of the spring are stretched with the rope (or compressed with other methods), when the rope is broken, or when other parts are relaxed, the elasticity of the spring will not disappear instantly?
- 18. Why does the tension of the rope change suddenly while the spring and elastic rope can't change suddenly
- 19. About springs, rubber ropes and ropes! Isn't the tension constant at the moment when the spring and the rubber rope break? For example, when the rope and the spring are used to bolt a heavy object and a wooden pole respectively, the tension of the spring on it doesn't change at the moment when it is cut? Here is a question that is a little incomprehensible: "in children's bungee jumping," the elastic rubber rope tied to the left and right sides of the waist is excellent, The tension of the two rubber ropes is just Mg (that is, the angle between the two of the three ropes is 120 degrees). The moment when the rubber rope on Xiaoming's left side breaks () why is the answer: acceleration a = g, the direction is opposite to the original tension direction of the broken rubber rope? The speed keeps the same with the situation. But the analysis of acceleration means that the rubber rope on the left side breaks, and because of the instantaneous invariance of the rubber rope, So the tension of the right rubber rope is constant, so the acceleration is g, which is opposite to the original tension direction of the broken rubber rope. My idea is that the left rubber rope should also have instantaneous invariance? Please answer my question comprehensively
- 20. Does the elasticity of spring and rope disappear immediately? Can the elasticity of spring be regarded as constant? Why does the book say that the spring force "can often be regarded as constant"?