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A moving pulley is used to lift an object with a weight of 200N upward for 3M within 5S, and the pulling force is 150n. What is the mechanical efficiency of the moving pulley? What is the power of the pulling force?
Free end movement of pulling rope s = 2H = 2 * 3 = 6M
Total work w = FS = 150 * 6 = 900j
Useful work W '= GH = 200 * 3 = 600J
Mechanical efficiency = w '/ w = 600 / 900 = 0.67 = 67%
Power of pulling force P = w / T = 900 / 5 = 180W
As shown in the figure, it is known that the inclined plane is 5m long and 2m high, and the pulling force is 50N. Using this device, an object weighing 100N & nbsp; is pulled from the bottom of the inclined plane to the top at a constant speed within 5S. Then the power of the pulling force is___ &Nbsp; W, for___ ．
(1) The effective work is equal to the work done by directly lifting the object at a constant speed of 2m; W useful = GH = 100N × 2m = 200J; (2) the total work done by the pulling force w total = FS = 50N × 2 × 5m = 500J; (3) the power of the pulling force is p = w total T = 500j5s = 100W; (4) the mechanical efficiency of the moving pulley is: η 1 = ghfl × 1005 = 100N × 2m50n × 2 × 5m × 100% = 40%; η 2 = w useful w total × 100% = 200j500j × 100% = 40% 4 × 0.4 × 100% = 16%. So the answer is: 100; 16%
The length and height of the smooth slope are 5 m and 3 m respectively. In 5 s, if an object with a gravity of 100 N is pulled from the bottom of the slope to the top of the slope, then
Then the following statement is correct: a. the required pulling force is 50N. B. the pulling force does 500J work on the object. C. the power of the pulling force is 60W. D. the mechanical efficiency of the inclined plane is 60%
A error, FS = GH, f = GH / S = 100 (3 / 5) = 60N
B error, w = FS = 60 * 5 = 300j
C is correct, P = w / T = 300 / 5 = 60W
D error, because the slope is smooth, so the mechanical efficiency is 100%
The object with a mass of 5kg starts to move for 5S (g = 10) under the action of a vertical upward tension f = 100N
1. The displacement of the object in 5S 2. What is the work done by the pulling force F 3.) what is the power of the pulling force in 5S 4.) what is the power of the final pulling force in 5S
1. First calculate the acceleration a = (f-mg) / M = (100-5 * 10) / 5 = 10 (M / S2), then the displacement in 5S is equal to s = 1 / 2 * a * T ^ 2 = 1 / 2 * 10 * 5 ^ 2 = 125 m2. The work done by pulling force F = f * s = 100 * 5 = 500 nm. 3. The velocity at the end of 5S is v = a * t = 10 * 5 = 50 (M / s)
Use a movable pulley to lift a 200N object up for 3M within 5S, and the pulling force is 150n. What is the power of the pulling force?
180w
The pulley block as shown in the figure is used to lift the heavy object. The weight of the object is known to be 200N. When a person pulls down the rope with a pull force of 125N, the object can rise at a constant speed of 2m within 5S. The following results are obtained: (1) the work done by the pull force and the power of the pull force; (2) the mechanical efficiency of the pulley block
(1) Moving distance of pulling force: S = NH = 2 × 2m = 4m, work done by pulling force: w = FS = 125N × 4m = 500J, power of pulling force: P = wt = 500j5s = 100W; (2) mechanical efficiency of pulley block: η = g, NF = 200n2 × 125N = 80%; answer: (1) work done by pulling force is 500J, power of pulling force is 100W. (2) mechanical efficiency of pulley block is 80%
The pulley block can not only save labor but also change the direction of force. When the pulley block is used to lift a 500N weight, the free end tension is 200N, and the weight rises at a uniform speed of 0.2m/s
Regardless of friction and rope weight, the weight of moving pulley? The power of pulling force? The mechanical efficiency of the pulley block =? When the heavy object is not lifted, the mechanical efficiency of the pulley block becomes larger / smaller / unchanged?
The weight of the moving pulley is 100, the power of the pulling force is p = FV, P = 40. The mechanical efficiency is 5 / 6. When lifting other heavy objects, the mechanical efficiency will change. When lifting heavier objects, the efficiency will be improved, and when lifting lighter objects, the efficiency will be reduced, but the lifting also has a certain weight. It is within the capacity range
Use the pulley block to lift a 20n weight and make it rise 0.4m. The tension acting on the free end of the rope is 8N. The point of action of the tension rises 1.2m. The work done by the tension is______ J. This merit is called______ Work. The work done by a pulley to overcome the gravity of an object is______ J. This merit is called______ &What is the work done to overcome the gravity and friction of the pulley______ J. This merit is called______ What is the mechanical efficiency of this pulley block______ ．
(1) The total work of pulling force: wtotal = FS = 8N × 1.2m = 9.6j, (2) the useful work of pulley overcoming gravity: wtotal = GH = 20n × 0.4m = 8j, (3) ∵ wtotal = wtotal + W, the additional work of overcoming gravity and friction of pulley: wtotal - wtotal = 9.6j-8j = 1.6j, (4) pulley
The pulley block is used to lift a weight of 20n to make it rise 0.4m. The tension acting on the free end of the rope is 8N, and the point of action of the tension rises 1.2m?
The work of pulling force is: w = FS = 8N * 1.2m = 9.6j
This work is called total work
As shown in the figure, the pulley block is used to lift the object with 630n weight, the free end tension F of the rope is 300N, and the weight rises at a uniform speed of 0.2m/s, regardless of friction and rope weight (1) The mechanical efficiency of the pulley block; (2) the power of pulling force; (3) whether the mechanical efficiency of the pulley block changes when lifting a heavy object with the pulley block under the condition of not exceeding the maximum pulling force that the rope can bear? Why?
(1) A: the mechanical efficiency of the pulley block is 70%. (2) V f = 3 V object = 3 × 0.2m/s = 0.6m/s, P = f v = 300N × 0.6m/s = 180W. A: the power of pulling force to do work is 180W. (3) it becomes larger because η = GG + G, the weight of the moving pulley remains the same, and the additional work remains the same. The heavier the object is, the more work there is, so the mechanical efficiency becomes larger
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