# data[].attributes.body
the action or process of moving or being moved.

# data[].attributes.body
strength or energy as an attribute of physical action or movement

# data[].attributes.attachment_link.readable_text
Lack of knowledge about torque can often mislead buyers to inaccurate choices when choosing an actuator for their automation package. Here is a clear definition of what actuator torque is.

Actuator torque is a numerical expression of the amount of torque that an actuator is capable of generating. Torque is a term used to define the extent to which a motive energy twists an object around its own axis or a point. A good example of this is a high-performance race car which tends to twist or lift on one side when the engine is revved. This reaction is caused by the engine's torque, which, although its output force is harnessed to drive the car forward along its own axis, exerts a rotational movement around the car's axis. In simple terms, the more torque a device can generate, the more power it will be able to exert over a wider range of operational loads.

The straight line motion experienced when something is pushed is a practical display of force. Torque, on the other hand, is best described as the result of the use of force to a wrench, which turns a bolt around its axis. The same applies to a screwdriver being used to loosen a very tenacious screw. If the screwdriver handle is well-designed and does not slip in one's hand, a large amount of torque is being generated and applied to the screw by the force applied to the screwdriver handle. The same principles regarding the conditions that influence the ability of comparable forces to generate rotary motion also apply to the definition of actuator torque.

Actuator torque is an important part of the rating specifications of any actuator. The torque rating of the device will determine what type of applications the actuator will realistically be able to handle. A low torque rating will mean that the actuator will be able to maintain its output force over a very narrow load range. As soon as that range is exceeded, the actuator will be "overwhelmed" and will not be able to continue exerting its working motion efficiently. In contrast, a high-torque actuator will be able to comfortably handle a far wider range of load variations.

This concept of actuator torque is perhaps best demonstrated by an automobile approaching a steep hill in top gear. In this gear configuration, the engine is not able to develop much torque and, to efficiently climb the hill, a lower gear will have to be selected. The same principle applies to an actuator with internal mechanism designs determining how well the actuator motor converts its force into usable torque. High torque values are not always called for, so not all actuators develop the same torque outputs even though they may have comparable power sources. This makes educated choices critical when selecting devices for applications requiring high actuator torque values.

Torque = T ; Force = F ; Distance = D

A force about a given axis that produces rotation has a moment (torque). The magnitude of the moment is the product of the force (F) and the perpendicular distance (D) from the line of action of the force to the axis, T=F x D. Simply put torque is generated by a twisting force which produces rotation about an axis.

# data[].attributes.attachment_link.title
3 Ways to Define Actuator Torque in Words You Understand

# data[].attributes.attachment_link.description
Lack of knowledge about torque can often mislead buyers to inaccurate choices when choosing an actuator for their automation package. Here is a clear definition of what actuator torque is. Actuator torque is a numerical expression of the amount of torque that an actuator is capable of generating.

# data[].attributes.body
a coherent, typically large body of matter with no definite shape.

# data[].attributes.body
the force that attracts a body toward the center of the earth, or toward any other physical body having mass..

# data[].attributes.body
a tendency to do nothing or to remain unchanged.

# data[].attributes.body
the speed of something in a given direction.

# data[].attributes.body
a vehicle's capacity to gain speed within a short time.

# data[].attributes.body
the resistance that one surface or object encounters when moving over another

# data[].attributes.body
Formally stated, Newton's third law is: For every action, there is an equal and opposite reaction.

# data[].attributes.attachment_link.readable_text
A force is a push or a pull that acts upon an object as a results of its interaction with another object. Forces result from interactions! As discussed in Lesson 2, some forces result from contact interactions (normal, frictional, tensional, and applied forces are examples of contact forces) and other forces are the result of action-at-a-distance interactions (gravitational, electrical, and magnetic forces). According to Newton, whenever objects A and B interact with each other, they exert forces upon each other. When you sit in your chair, your body exerts a downward force on the chair and the chair exerts an upward force on your body. There are two forces resulting from this interaction - a force on the chair and a force on your body. These two forces are called action and reaction forces and are the subject of Newton's third law of motion. Formally stated, Newton's third law is:

For every action, there is an equal and opposite reaction.

The statement means that in every interaction, there is a pair of forces acting on the two interacting objects. The size of the forces on the first object equals the size of the force on the second object. The direction of the force on the first object is opposite to the direction of the force on the second object. Forces always come in pairs - equal and opposite action-reaction force pairs.

Examples of Interaction Force Pairs

A variety of action-reaction force pairs are evident in nature. Consider the propulsion of a fish through the water. A fish uses its fins to push water backwards. But a push on the water will only serve to accelerate the water. Since forces result from mutual interactions, the water must also be pushing the fish forwards, propelling the fish through the water. The size of the force on the water equals the size of the force on the fish; the direction of the force on the water (backwards) is opposite the direction of the force on the fish (forwards). For every action, there is an equal (in size) and opposite (in direction) reaction force. Action-reaction force pairs make it possible for fish to swim.

Consider the flying motion of birds. A bird flies by use of its wings. The wings of a bird push air downwards. Since forces result from mutual interactions, the air must also be pushing the bird upwards. The size of the force on the air equals the size of the force on the bird; the direction of the force on the air (downwards) is opposite the direction of the force on the bird (upwards). For every action, there is an equal (in size) and opposite (in direction) reaction. Action-reaction force pairs make it possible for birds to fly.

Consider the motion of a car on the way to school. A car is equipped with wheels that spin. As the wheels spin, they grip the road and push the road backwards. Since forces result from mutual interactions, the road must also be pushing the wheels forward. The size of the force on the road equals the size of the force on the wheels (or car); the direction of the force on the road (backwards) is opposite the direction of the force on the wheels (forwards). For every action, there is an equal (in size) and opposite (in direction) reaction. Action-reaction force pairs make it possible for cars to move along a roadway surface.

Check Your Understanding

1. While driving down the road, a firefly strikes the windshield of a bus and makes a quite obvious mess in front of the face of the driver. This is a clear case of Newton's third law of motion. The firefly hit the bus and the bus hits the firefly. Which of the two forces is greater: the force on the firefly or the force on the bus?

2. For years, space travel was believed to be impossible because there was nothing that rockets could push off of in space in order to provide the propulsion necessary to accelerate. This inability of a rocket to provide propulsion is because ...

a. ... space is void of air so the rockets have nothing to push off of.

b. ... gravity is absent in space.

c. ... space is void of air and so there is no air resistance in space.

d. ... nonsense! Rockets do accelerate in space and have been able to do so for a long time.

3. Many people are familiar with the fact that a rifle recoils when fired. This recoil is the result of action-reaction force pairs. A gunpowder explosion creates hot gases that expand outward allowing the rifle to push forward on the bullet. Consistent with Newton's third law of motion, the bullet pushes backwards upon the rifle. The acceleration of the recoiling rifle is ...

a. greater than the acceleration of the bullet.

b. smaller than the acceleration of the bullet.

c. the same size as the acceleration of the bullet.

4. In the top picture (below), Kent Budgett is pulling upon a rope that is attached to a wall. In the bottom picture, Kent is pulling upon a rope that is attached to an elephant. In each case, the force scale reads 500 Newton. Kent is pulling ...

a. with more force when the rope is attached to the wall.

b. with more force when the rope is attached to the elephant.

c. the same force in each case.

# data[].attributes.attachment_link.description
Newton's third law of motion describes the nature of a force as the result of a mutual and simultaneous interaction between an object and a second object in its surroundings. This interaction results in a simultaneously exerted push or pull upon both objects involved in the interaction.

# data[].attributes.body
Newton's second law of motion can be formally stated as follows:

# data[].attributes.body
Newton's first law of motion - sometimes referred to as the law of inertia.An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.