When the direction of the pulling force of the movable pulley changes, does its pulling force change

Yes. When it is vertically up (down), the pulling force is the smallest, because at this time the power arm is the longest, which is the diameter of the circle;

The greater the declination angle to the vertical, the greater the tensile force used, because the power arm will become shorter and will be a round chord (not the diameter);

Principle: L1 F1 L2 F2 (Power Arm Power Resistance Arm Resistance Hope it can help you!)

A movable pulley is a common simple machine that consists of a fixed pulley and a movable pulley, which can move with the movement of a rope or chain. When moving pulleys are used to pull heavy objects, less pulling force can be used to move heavier objects.

When the direction of the pulling force of the movable pulley changes, its pulling force does not necessarily change. This is because the pulling force of the movable pulley is generated by the pulling force of the rope, and the pulling force of the rope is along the direction of the rope and has nothing to do with the direction of the pulling force. Therefore, as long as the direction of the pulling force coincides with the direction of the rope, the pulling force of the rope will not change no matter how the direction of the pulling force changes.

However, when the direction of the pulling force is perpendicular to the direction of the rope, the pulling force of the rope will be maximum, and the change in the direction of the pulling force will affect the tension of the rope. Therefore, when applying movable pulleys, it is necessary to select the appropriate direction and size of tension according to the actual situation to meet the requirements.

Yes, in this way, the fulcrum will not change, and the power arm will change, and according to Archimedes' law [Lever Theorem], it can be concluded that the tensile force will change.

Yes, the larger the declination angle with the vertical, the greater the tensile force used, which is the consequence of the constant resistance arm and the smaller power arm.

I guess that's right. Beg.

Because it lifts upwards in the same direction as the object moves, the direction of the force is upward, while the direction of the object is the same, so it does not change.

The moving pulley can make the object move upward, the object is originally moving upward, so it has not changed, as for the result of changing the direction, because it should not be changed, it should be that the object is always moving upward, it can only be said that the direction of changing the power is the direction of pulling the rope, and if it is changed, it will not be able to achieve the result of saving half of the force, and the power will be greater than one-half g.

Features:

The use of movable pulleys can save half the effort and consume the distance. This is because when using movable pulleys, the hook is suspended by two sections of rope, each of which bears only half the weight of the hook. Although the use of movable pulleys saves effort, the distance of power movement is twice the distance raised by the hook code, that is, the distance is charged.

The direction of the force cannot be changed. Moves as the object moves. In addition, the quality of the movable pulley itself cannot be ignored in life, so extra work is done in the process of the movable pulley rising to reduce the mechanical efficiency.

1. The movable pulley does not change the direction of the force. - This refers to the conclusion when "pulling vertically".

2. When the movable pulley is pulled diagonally, the direction of the force is changed. At this time, it is not 1 times the labor-saving. See instructions below.

The movable pulley is not always a labor-saving lever with the power arm being twice that of the resistance arm, and is related to the direction of the power (pulling force).

As shown in the figure, f2 is the resistance, and the direction is vertical downward; F1 is the power, the application point is point A, and the direction is vertical and upward. According to the definition of the arm of the force, it can be obtained: l1=2r; l2=r。At this time, the power arm is twice as large as the resistance arm.

Therefore, for movable pulleys, changing the direction of power, the force arm changes, and the moving pulley is not always a force-saving lever where the power arm is 2 times that of the resistance arm. Only when the line of action of the dynamic force is parallel to the line of action of the resistance, the power arm is equal to twice the arm of the resistance; When the dynamic line is not parallel to the resistance line, the ratio of the power arm to the resistance arm is less than 2.

I hope it helps you, and if you have any questions, you can ask them

I wish you progress in your studies and go to the next level! (*

The attached drawings are as follows:

The pulley that moves with the pulley group is called the moving pulley, such as the vertical pulley, which moves with the force, so it can only reduce the force and cannot change the direction of the force.

They are used as power arms and resistance arms respectively, and they are not labor-saving when pulling obliquely.

I guess it's pulling diagonally like you said.

This is not important, as long as you remember that the characteristics of the fixed pulley are that it can change the direction of the force but does not save force, and the movable pulley cannot change the direction of the force but can save the force.

The movable pulley does not change the direction of the force. - This refers to the conclusion when "pulling vertically".

When the movable pulley is pulled diagonally, the overall direction of movement is still upward.

First of all, for example, the flagpole is a fixed pulley, you think, if you want to raise the national flag, do you want to pull it up to the top of the flagpole? So with a fixed pulley, the force you use is straight down, which doesn't change the direction of the force.

Then, this pulling force is the spring scale indication to multiply the distance traveled by the spring scale, which is twice the distance the object moves.

For example, if the moving pulley moves at a constant speed of 1 meter under the action of the spring scale tension, and the spring scale shows 5 Newtons, then the spring scale pulls 5 * 1 * 2 = 10j, 9, you have a problem with this question, and you have not made it clear! , 2, change the direction of the power.

If an object wants to move upwards and you can give it a downward force.

w = 2 times the force on the fs f spring scale.

Because it is necessary to overcome the work done on the frictional force, 1, because the rope changes the direction of the pull through the fixed pulley, the force above will naturally change the direction, 0, why can the fixed pulley change the direction of the force How to change?

If you have a moving pulley, where the weight is placed on a horizontal plane, how do you solve a similar problem?

It is a moving pulley placed horizontally, and the weight is placed on the Dan level dug carry, and the spring is called to pull it, and this kind of pulling workmanship should be calculated.

Summary. When we use pulleys to change the direction of force, the number of fixed pulleys and movable pulleys needs to be equal, because in the pulley system, with each additional pulley, the pulling force will decrease, but the length of the rope that needs to be pulled will increase. Therefore, if there is only one movable pulley, but there are multiple fixed pulleys, then the length required to pull the rope increases dramatically because the magnitude of the force does not change with the number of pulleys.

If the number of movable pulleys is increased, the length of the rope required can be effectively reduced, so as to change the direction of the force more efficiently.

Why is it necessary to change the direction of the force, and the number of fixed pulleys and movable pulleys should be equal?

Thank you. When we use pulleys to change the direction of force, the number of fixed pulleys and movable pulleys needs to be equal, this is because in the pulley system, each additional pulley, the rounding force will decrease, but the length of the rope that needs to be pulled will increase. Therefore, if there is only one movable pulley, but there are multiple fixed pulleys, then the length required to pull the rope increases dramatically because the magnitude of the force does not change with the number of pulleys.

If you increase the number of movable pulleys, you can quietly and effectively reduce the length of the rope required, so as to change the direction of the force more efficiently.

Therefore, in order to make the pulley system more efficient, the number of fixed pulleys and movable pulleys needs to be equal. Intuitively, you can imagine the direction of the rope in the pulley system, if the number of socks and potato wheels exceeds the movable pulley, then the direction of the rope will become very complicated, and vice versa, it will become simple and clear, because the position of the movable pulley determines the direction of the tension. I hope my Chun Hao Chun can help you

The direction of F1 and F2 is not the same, and the size is not the same, F1 is equal to one-half of the weight of the rock mass, and F2 is greater than one-half of the weight of the lead Luyu's object, but they are all equal to the force on the other side of the rope on the other side of the movable pulley, and if the force is applied by F2, the figure is not what it is now in the equilibrium state, and the moving pulley will move to the side in the direction of the force; F3 and F4 are also in different directions, but the size is the same, which is equal to the weight of the object, that is, the gravitational force experienced by the object.

Summary. Kiss! We are glad to answer for you, the magnitude of sliding friction is related to the roughness of the contact surface and the magnitude of the pressure, the rougher the contact surface and the greater the pressure, the greater the sliding friction; Because friction always hinders the relative motion of the object, therefore, its direction is always opposite to the direction of the relative motion of the object The influencing factors of sliding friction are two, the roughness of the contact surface and the positive pressure, which are generally unchanged in motion.

Static friction is the existence of the object when it is not moving, and it will change with the change of external force, and the net force in the equilibrium state needs to be considered to indirectly find the static friction force. The direction of the uniform linear motion does not change, and the linear motion is accelerated uniformly.

Why is sliding friction a variable force and why does the direction change all the time.

Kiss! We are glad to answer for you, the magnitude of sliding friction is related to the roughness of the contact surface and the magnitude of the pressure, the rougher the contact surface and the greater the pressure, the greater the sliding friction; Because friction always hinders the relative motion of the object, therefore, its direction is always opposite to the direction of the relative motion of the object The influencing factors of sliding friction are two, the roughness of the contact surface and the positive pressure, which are generally unchanged in motion. Static friction is the existence of the object when it is not moving, and it will change with the change of external force, and the net force in the equilibrium state needs to be considered to indirectly find the static friction force.

The direction of the uniform linear motion does not change, and the linear motion is accelerated uniformly.

On an inclined plane, the block is going to slide down the inclined plane, and the sliding friction it is subjected to is a variable force.

On an inclined plane, the block slides down the slope, and the direction of the sliding friction it experiences changes all the time.

The object is supported by gravity and oblique forces, and if the contact surface is rough, there may also be sliding friction, which is in the same direction and opposite to the direction of motion.

Unless the bevel is of a different material.