Glossary of magnetic terminology
How to navigate the world of neodymium magnets?
Welcome to our comprehensive glossary dedicated to the fascinating world of neodymium magnets. As a leading expert in providing excellent magnetic solutions, we are aware of how essential it is to have a reliable information about the concepts in this unique field. This glossary has been meticulously prepared to serve as an key source of information for all those interested who is keen on magnets – whether or not you are an specialist, a hobbyist, or an enthusiast the applications of magnets.
In our glossary, you will find readable and comprehensive explanations of important notions and subjects related to neodymium magnets. From the principles of magnetic fields and flux density, to material characteristics and magnetic innovations, each definition has been designed to expand your understanding and ease the comprehension of even the sophisticated ideas. If you are researching industrial applications, conducting scientific experiments, or simply curious magnetism, this glossary aims to support your learning.
Dive into the captivating world of neodymium magnets with confidence. Broaden your understanding, gain fresh perspectives, and unlock the potential of these exceptional materials, understanding terms and theories that define their functionality and utility. Consider this glossary as your guide in exploring the developing domain of magnetic technology.
Litera: A
The air gap is the distance filled with air that separates a magnet from another object. Increasing the gap weakens the attractive force. Formula: B = μ0(H - M), where:
B - magnetic induction,
μ0 - permeability of free space,
H - magnetic field strength,
M - magnetization.
B - magnetic induction,
μ0 - permeability of free space,
H - magnetic field strength,
M - magnetization.
An anisotropic material, e.g., neodymium magnets, has properties dependent on orientation. Anisotropic magnets are stronger than isotropic magnets, but they can only be magnetized along a specific axis.
Annealing is a heat treatment process in magnetic materials. It is performed at high temperatures, usually in a protective atmosphere to prevent material degradation. Annealing enhances the magnetic properties and allows for better performance in applications.
Axial magnetization means that the magnetic poles are distributed along the axis of the magnet, and the magnetic field lines run parallel to its axis. This configuration is commonly used in cylindrical and ball-shaped magnets. Formula: Bz = (Br/2) × [(L + 2z) / (L² + 4z²)0.5 - (L - 2z) / (L² + 4z²)0.5].
Litera: B
Magnetic induction B is the field intensity passing through a unit area. It is measured in teslas. Formula: B = μ0(H + M), where:
μ0 - permeability of free space,
H - external magnetic field strength,
M - magnetization.
μ0 - permeability of free space,
H - external magnetic field strength,
M - magnetization.
The hysteresis loop is a chart of the relationship between magnetic induction (B) and magnetizing force (H). It helps determine properties like magnetic energy loss. The hysteresis loop is a fundamental tool in evaluating materials used in electric motors.
Remanent induction Bd is the residual magnetic field in a material after the external magnetic field is removed. It is measured or gauss and represents the material's ability to retain magnetism.
The slope of the operating line, denoted as Bd/Hd, is the a coefficient describing magnetic permeability. Formula: Bd/Hd = (Br - Hd) / Hd. This is a key parameter in the design of magnetic circuits.
Bg represents the average magnetic induction in the air gap. It is a critical parameter in designing devices such as sensors and actuators. Formula: Bg = Φ / A, where:
Φ - magnetic flux,
A - air gap area.
Φ - magnetic flux,
A - air gap area.
Litera: C
The C.G.S. system of units is one of the oldest measurement systems. Despite being succeeded by the MKSA (SI) system, C.G.S. is still relevant in historical and specialized analyses. This system includes units for magnetizing force and magnetic induction.
A closed circuit refers to a configuration where there are no breaks or interruptions. It uses high-permeability materials to ensure continuity of magnetic field flow. They are critical in applications requiring controlled magnetic fields.
Coercive force, denoted as Hc, is the necessary strength to demagnetize a material. This parameter measures the material's resistance to demagnetization. Formula: Hc = -M/χ, where:
M - magnetization,
χ - magnetic susceptibility.
M - magnetization,
χ - magnetic susceptibility.
High coercivity indicates the durability of a material's magnetic properties. It also affects magnetic stability under varying conditions.
Intrinsic coercivity, denoted as Hci or iHc, represents the ability to maintain its magnetic properties. It measures the demagnetizing force acting on intrinsic induction (Bi). Materials with high coercivity offer magnetic stability.
Curie temperature is the point at which ferromagnetic materials lose their magnetic properties. Beyond this temperature, the material ceases to exhibit strong magnetic behavior. Formula: Tc = (2kB / μ0) × J02 / χ, where:
kB - Boltzmann constant,
J0 - magnetic moment.
kB - Boltzmann constant,
J0 - magnetic moment.
Litera: D
Demagnetization refers to the process of weakening residual induction in a material. Methods include applying alternating magnetic fields, heating above the Curie temperature. This process is essential in applications requiring precise control of magnetization.
The demagnetization curve illustrates the relationship between magnetic induction (B) and magnetizing force (H). It reveals the material's hysteresis characteristics, including coercivity and remanent induction. This tool is vital for analyzing magnetic material characteristics.
Demagnetization force refers to the opposing magnetic field that induces demagnetization. This force allows for controlling the level of magnetization in materials.
A demagnetized material is one where remanent induction has been reduced to zero. This state is achieved through or other demagnetization techniques such as heating. Demagnetization is important in applications requiring neutral magnetic properties.
approximately 7.5 g/cm³, is one of the key parameters defining its magnetic properties. Density can be approximately determined using the formula:
ρ = m / V, where:
ρ - density (in g/cm³ or kg/m³),
m - mass of the magnet (in grams or kilograms),
V - volume of the magnet (in cm³ or m³).
Example: For a magnet with a mass of 150 g and a volume of 20 cm³, the density is:
ρ = 150 / 20 = 7.5 g/cm³.
Knowing the density helps predict the magnet's strength and durability.
ρ = m / V, where:
ρ - density (in g/cm³ or kg/m³),
m - mass of the magnet (in grams or kilograms),
V - volume of the magnet (in cm³ or m³).
Example: For a magnet with a mass of 150 g and a volume of 20 cm³, the density is:
ρ = 150 / 20 = 7.5 g/cm³.
Knowing the density helps predict the magnet's strength and durability.
Diamagnetic materials exhibit no permanent magnetic moment. When exposed to an external field, they generate an opposing field. This behavior results from induced currents within the material.
Diameter refers to the distance between the farthest points across the surface of or other geometric shape. It is a critical parameter in designing magnetic systems.
Diametrically magnetized magnets have poles located on opposite sides of the diameter. They are commonly used in applications requiring radial or rotational interactions.
Dimensional tolerance specifies the range of variation in magnet size. It is crucial for integrating magnetic components into systems.
Dimensions refer to the measurable physical properties of a magnet. Accurate dimensioning is key to ensuring the proper functionality of magnetic systems.
The direction of magnetization defines the orientation of magnetic domains. This is a critical feature that affects the material's magnetic behavior.
Domains are microscopic regions where creating localized magnetic fields. They can be altered by external magnetic fields, temperature, or stress.
Litera: E
Eddy currents are circulating currents created in conductive materials when exposed to changing magnetic fields. They cause energy losses, heating, or resistive effects. The use of laminated cores or magnetic shielding minimizes their impact and enhances performance.
An electromagnet is a magnet that relies on an electric coil to produce a magnetic field. The strength of the magnetic field depends on the current. Electromagnets are applied in such as motors, generators, or MRI systems.
The energy product is an indicator of a magnet's ability to supply energy. It is calculated as the product of magnetic induction (Bd) and magnetizing force (Hd). Expressed in MGOe (Mega Gauss Oersteds) or kJ/m³, it is a critical parameter for evaluating their efficiency in applications.
Measured as the product of the material's remanence and coercivity. This parameter is essential in evaluating the performance and strength of a magnet in industrial applications.
Litera: F
Ferrites are substances primarily composed of iron oxide (Fe2O3). Renowned for their high-frequency properties. Used in transformers, inductors, and telecommunication devices.
A ferromagnetic material is characterized by strong magnetic properties. In such materials, atoms generate a strong magnetic field. Examples include and their alloys. These materials are fundamental due to their permanent magnetic properties.
Flux density, denoted as B, defines the strength of the magnetic field. Measured in standard magnetic units, it is a crucial parameter for evaluating magnet performance.
A fluxmeter is used to measure magnetic induction (B). It employs various technologies such as the Hall effect or rotating coil techniques. It is a critical engineering tool.
Litera: G
Gauss is named after German physicist Carl Friedrich Gauss. One Gauss (G) equals a smaller scale of magnetic induction. Commonly used in laboratory applications.
A Gauss meter is a device for measuring magnetic field strength. or other techniques to read values in Gauss (G) or Tesla (T). Helpful in magnetic diagnostics.
The Gilbert is named after William Gilbert, a pioneer in magnetic research. One Gilbert represents the field strength needed to produce magnetic flux in a specific circuit.
The grade of a magnet refers to its magnetic properties, such as BHmax or Hc. Higher grades offer greater resistance to temperatures and demagnetizing forces.
Litera: H
A Hall sensor operates on the principle of the Hall effect, which involves inducing a voltage in a conductor in the presence of a magnetic field. These devices play a crucial role in industrial automation and precision measurements.
Coercive force (Hc) represents a measure of a material's resistance to demagnetization. Expressed in SI units, higher Hc values indicate resistance to external influences.
Hd denotes the magnetic field strength required to achieve a specific remanent induction (Bd). Measured in various magnetic units.
A high field gradient magnet produces strong and rapidly changing magnetic fields. Applications include and scientific research requiring advanced field parameters.
Hm represents a key parameter in magnetic system design. It is critical for designing systems requiring high magnetic fields.
A homogeneous field is characterized by a lack of intensity variations over a given area. It is crucial for applications requiring precise magnetic fields.
A horseshoe magnet has its poles placed close together. Popular in education, metal detection.
Net effective magnetizing force (Hs) refers to an essential parameter for analyzing the magnetic properties of materials. Measured in oersteds (Oe) or kiloamperes per meter (kA/m).
The hysteresis graph, also called a permeameter, illustrates the magnetic characteristics of materials. It is used in and optimizing magnetic designs.
The hysteresis loop is a graphical representation of the relationship between magnetic induction (B) and magnetizing force (H). It provides information about energy losses, coercivity, and energy storage capacity.
Hysteresis refers to a material's ability to retain partial magnetization after the external field is removed. Hysteresis loss is a transformation of energy into heat. crucial for designing transformers and motors.
Litera: I
Inner diameter (ID) refers to the internal dimension of a hollow object, such as a magnet, tube, or ring. It is an essential parameter in magnetic circuit design.
Magnetic induction (B) describes the strength of the magnetic field in a material or space. It is measured in standard SI units. Essential for designing and analyzing magnetic systems.
Irreversible losses refer to the effects of high temperatures, mechanical stress, or demagnetizing fields. They result in challenges in long-term magnet usage.
An isotropic material is independent of magnetic field orientation. Often compared to anisotropic materials with direction-dependent properties.
Litera: K
A keeper is an accessory preventing demagnetization of magnets. helps maintain the magnet's strength. Used primarily with Alnico magnets or older designs.
Kilogauss (kG) is a unit used to express magnetic induction or flux density. 1 kilogauss = 1000 Gauss. Commonly used in scientific research, magnet testing.
Litera: L
The load line represents the operating points of a magnetic material on the demagnetization curve. useful for optimizing magnetic applications.
Lodestone is the first known natural magnet. possesses unique properties due to its magnetic domain alignment.
Litera: M
A magnet is an object producing a magnetic field with magnetic poles. Can be natural, like lodestone, or artificial, such as neodymium.
A magnetic assembly is designed to achieve specific magnetic properties. Used in sensors, magnetic separators.
The magnetic axis is an imaginary line within a magnet where the magnetic field is most concentrated or intense. essential for analyzing the magnet's behavior and interactions with other magnetic components.
A magnetic circuit is a path through which magnetic flux flows. Comprises magnetic materials, air gaps, and other components.
Magnetic energy is the energy stored within a magnetic field. Important in applications like magnetic resonance imaging or magnetic generators.
A magnetic field (B) is an area where magnetic materials or electric charges experience a magnetic force. created by magnets or electric currents.
Magnetic field strength (H) is the intensity of the magnetic field in a circuit. Depends on the current flowing through the conductor.
Magnetic flux is the number of magnetic field lines passing through a specific area. Expressed in webers (Wb).
Magnetic flux density, denoted as B, is a measure of the strength or concentration of a magnetic field. It represents the amount of magnetic flux passing through a unit area.
It is expressed by the formula:
B = Φ / A
Where:
B: Magnetic flux density (Tesla, Gauss)
Φ: Magnetic flux (Weber)
A: Surface area (m²)
If the area is 0.05 m² and the magnetic flux is 0.002 Weber, the resulting flux density is 0.04 Tesla.
A high B value indicates a stronger magnetic field, essential in industrial and medical applications.
It is expressed by the formula:
B = Φ / A
Where:
B: Magnetic flux density (Tesla, Gauss)
Φ: Magnetic flux (Weber)
A: Surface area (m²)
If the area is 0.05 m² and the magnetic flux is 0.002 Weber, the resulting flux density is 0.04 Tesla.
A high B value indicates a stronger magnetic field, essential in industrial and medical applications.
The hysteresis loop illustrates the behavior of magnetic materials during cycles of magnetization and demagnetization. Materials with a narrower loop have lower energy losses.
expressed in units like teslas (T) in the SI system or gausses (G) in the CGS system. Magnetic flux density is a key parameter in designing magnetic systems.
A magnetic line of force, also known as a magnetic field line, is an imaginary curve representing the direction and shape of a magnetic field. The density of field lines reflects the strength of the field at various locations.
A magnetic path refers to the route taken by magnetic flux in a magnetic circuit or system. minimizes magnetic losses.
Magnetic permeability defines a material's ability to conduct magnetic flux. Materials with high permeability are more effective at concentrating magnetic fields.
Every magnet has a north and south pole. Understanding pole interactions is crucial in designing magnetic systems.
Magnetic saturation describes the maximum magnetic field intensity a material can achieve. This parameter is vital when selecting materials for high-field applications.
Magnetization refers to the result of aligning atomic or molecular magnetic moments in a preferred orientation. It can be achieved by exposure to a magnetic field, electric current flow, or contact with other magnets.
Magnetization is the process of imparting magnetic properties to a material by aligning its magnetic domains. The ability to magnetize is crucial in designing permanent magnets and electromagnets.
A magnetization curve, also called a B-H curve or demagnetization curve, represents the relationship between magnetic field strength (H) and magnetic induction (B). useful for selecting materials for specific applications.
Magnetized refers to the state of a material possessing a magnetic field or being magnetized. Magnetized materials exhibit magnetic properties and can attract or repel other magnetic materials.
Magnetomotive force (mmf) is a measure of the ability to generate a magnetic field in a magnetic circuit. Expressed in ampere-turns (At) or gilberts (Gb).
In magnetism, material refers to classified as ferromagnetic, paramagnetic, or diamagnetic. Ferromagnetic materials like iron can be permanently magnetized.
Maximum energy product, denoted as BHmax, represents the peak capability of a magnet to store and release magnetic energy.
The formula for BHmax is:
BHmax = B × H
Where:
B: Magnetic flux density (Tesla)
H: Magnetic field strength (A/m)
For example, a magnet with B = 1 T and H = 600 kA/m achieves a BHmax of 600 kJ/m³.
High BHmax values are characteristic of neodymium magnets, making them indispensable for advanced industrial applications.
The formula for BHmax is:
BHmax = B × H
Where:
B: Magnetic flux density (Tesla)
H: Magnetic field strength (A/m)
For example, a magnet with B = 1 T and H = 600 kA/m achieves a BHmax of 600 kJ/m³.
High BHmax values are characteristic of neodymium magnets, making them indispensable for advanced industrial applications.
Maximum operating temperature (Tmax) is a crucial parameter for applications in high-temperature environments. Temperatures exceeding Tmax may result in material demagnetization.
Maxwell is a unit of magnetic flux named after James Clerk Maxwell. critical for historical and scientific magnetic applications.
Mega Gauss Oersteds (MGOe) is a unit used to express the amount of magnetic energy stored in a magnet per unit volume. This unit helps assess the magnetic potential of magnets in complex magnetic circuits.
A monopole refers to a hypothetical single magnetic pole existing independently as either a north or south magnetic pole. So far, monopoles have not been observed in nature.
Litera: N
N rating refers to a numerical designation, e.g., N35, N42, or N52, indicating the maximum energy product (BHmax). These ratings assist users in selecting appropriate magnets for specific applications.
The north pole is the pole that, when freely suspended, points toward the Earth's geographic North Pole. associated with the direction of outgoing magnetic field lines.
Litera: O
Oersted is a unit used to measure the intensity of the magnetic field (H). 1 oersted corresponds to the field that exerts a force of one dyne on a unit magnetic pole at a distance of one centimeter.
An open circuit refers to a condition where a magnetic circuit is not closed or complete. In this state, magnetic field lines cannot form a closed loop, leading to weakened magnetic fields.
Orientation refers to determines the direction and distribution of the magnetic field or flux. Proper orientation is critical to achieving desired magnetic properties and optimizing magnetic systems.
Litera: P
Paramagnetic materials are become magnetized in the direction of the external field due to the alignment of atomic or molecular magnetic moments. examples include aluminum, manganese, and oxygen.
Paramagnetism is occurs when materials develop a temporary magnetic moment in the direction of the field. examples include aluminum, platinum, and oxygen.
A permanent magnet is a material or object that retains its magnetic properties indefinitely. It is made from materials with strong magnetic properties, such as iron, nickel, or cobalt alloys.
Permanent magnets generate a magnetic field without the need for external power. Their durability and stability make them indispensable in many industrial applications.
Magnetic permeability is a property of a material determining its ability to conduct magnetic flux. the value of permeability depends on the chemical composition and structure of the material.
Magnetic permeability, denoted by the symbol P, is a measure of a material's ability to conduct magnetic flux.
The mathematical formula for permeance is expressed as:
P = (μ × A) / l
Where:
μ: Magnetic permeability of the material (H/m)
A: Cross-sectional area of the magnetic path (m²)
l: Length of the magnetic path (m)
For instance, a material with a large cross-sectional area and short magnetic path exhibits high permeance, making it efficient in magnetic applications.
Permeance is a key parameter in designing magnetic circuits, especially in applications requiring minimal magnetic losses.
The mathematical formula for permeance is expressed as:
P = (μ × A) / l
Where:
μ: Magnetic permeability of the material (H/m)
A: Cross-sectional area of the magnetic path (m²)
l: Length of the magnetic path (m)
For instance, a material with a large cross-sectional area and short magnetic path exhibits high permeance, making it efficient in magnetic applications.
Permeance is a key parameter in designing magnetic circuits, especially in applications requiring minimal magnetic losses.
The permeance coefficient is the ratio of remanence (Br) to coercive force (Hd) in a magnetic material. This coefficient impacts magnetic stability and parameters such as the energy product (BHmax) in magnetic circuits.
Provides protection against corrosion, oxidation, and demagnetization, enhancing the durability of magnets. Thanks to coatings, magnets can be used in harsh environmental conditions.
Polarity describes the orientation of the magnetic field in a neodymium magnet, which has two poles: north and south. Understanding the polarity of magnets is crucial for their proper application and alignment in various magnetic systems.
A magnetic pole refers to one of the two ends of a magnet where the magnetic field is strongest: north or south. Their location and properties are critical for optimizing performance in magnetic applications.
Pull force, also known as holding force, describes the force required to separate a magnet from a ferromagnetic surface. It can be estimated using the formula:
F = B² × A / (2 × μ₀), where:
F - Pull force (in newtons, N).
B - Magnetic flux density at the magnet's surface (in teslas, T).
A - Contact area of the magnet with the material (in m²).
μ₀ - Permeability of free space (4π × 10⁻⁷ H/m).
Example: If the magnetic flux density is 1.2 T, and the magnet's contact area is 0.005 m², the pull force is:
F = (1.2)² × 0.005 / (2 × 4π × 10⁻⁷) ≈ 572 N.
F = B² × A / (2 × μ₀), where:
F - Pull force (in newtons, N).
B - Magnetic flux density at the magnet's surface (in teslas, T).
A - Contact area of the magnet with the material (in m²).
μ₀ - Permeability of free space (4π × 10⁻⁷ H/m).
Example: If the magnetic flux density is 1.2 T, and the magnet's contact area is 0.005 m², the pull force is:
F = (1.2)² × 0.005 / (2 × 4π × 10⁻⁷) ≈ 572 N.
Litera: R
these magnets are known for their exceptional magnetic properties and wide applications. Due to their high magnetic strength, they are used in industries, electronics, and consumer technologies.
They are made from rare earth elements like neodymium, dysprosium, and praseodymium. Their high efficiency makes them indispensable in numerous applications.
Relative permeability is a measure of how easily a material can be magnetized compared to a vacuum. Neodymium magnets exhibit high relative permeability, enabling efficient design of magnetic circuits.
Reluctance is a measure of the opposition a magnetic circuit presents to the flow of magnetic flux. The design and geometry of the magnet and surrounding materials affect reluctance and the efficiency of magnetic circuits.
Reluctance, denoted by the symbol R, measures a magnetic circuit's opposition to magnetic flux.
The mathematical formula for reluctance is:
R = l / (μ × A)
Where:
R: Magnetic resistance (1/H)
l: Length of the magnetic path (m)
μ: Magnetic permeability of the material (H/m)
A: Cross-sectional area of the magnetic path (m²)
The larger the magnetic cross-section or permeability, the lower the magnetic resistance.
Understanding reluctance allows optimization of systems such as electromagnets, transformers, and electric motors.
The mathematical formula for reluctance is:
R = l / (μ × A)
Where:
R: Magnetic resistance (1/H)
l: Length of the magnetic path (m)
μ: Magnetic permeability of the material (H/m)
A: Cross-sectional area of the magnetic path (m²)
The larger the magnetic cross-section or permeability, the lower the magnetic resistance.
Understanding reluctance allows optimization of systems such as electromagnets, transformers, and electric motors.
Remanence, often denoted as Bd, is a measure of the residual magnetism remaining in a neodymium magnet after it has been saturated and the external magnetic field is removed. Allows for assessing the long-term stability and suitability of magnets for various applications.
This occurs due to opposing magnetic fields generated by the magnets, causing them to repel each other. The repulsive force is proportional to the magnetic strength and distance between the magnets.
Includes the use of ferromagnetic materials or magnetic conductors to guide the magnetic field. Is a critical component in designing efficient magnetic circuits.
Litera: S
Shear force, denoted by the symbol Fs, refers to the force required to displace a magnet along the contact surface in a direction parallel to the contact plane.
The formula for shear force is:
Fs = F × tan(θ)
Where:
F: Pull force (N)
θ: Angle of the contact surface (rad)
The greater the angle, the higher the force required to move the magnet.
Shear force is a crucial factor in designing magnetic systems, particularly where high mechanical stability is required.
The formula for shear force is:
Fs = F × tan(θ)
Where:
F: Pull force (N)
θ: Angle of the contact surface (rad)
The greater the angle, the higher the force required to move the magnet.
Shear force is a crucial factor in designing magnetic systems, particularly where high mechanical stability is required.
The south pole is one of the two fundamental magnetic poles of a magnet. Magnetic field lines flow from the north pole to the south pole, defining interaction properties.
This process involves arranging magnets in series or parallel configurations, enhancing the magnetic field. Such arrangements enable stronger magnetic interactions and improved performance in various applications, such as magnetic separators, holders, or sensors.
Litera: T
Tesla is a unit of measurement for magnetic flux density, describing the strength and intensity of a magnetic field. The unit is named after Nikola Tesla, a renowned inventor and physicist whose work revolutionized electromagnetism.
Isotropic magnets can be magnetized in any direction, making them versatile. Isotropic magnets are ideal for general applications due to their flexibility.
Litera: W
Named after Wilhelm Eduard Weber, a German physicist and pioneer of electromagnetic theory. Useful in analyzing magnet effectiveness in applications like generators, motors, and energy storage systems.
The weight of a neodymium magnet is an essential parameter influencing its applications. It can be easily calculated based on its density and volume using the formula:
m = ρ × V, where:
m - mass of the magnet (in grams or kilograms).
ρ - density of the magnet (typically 7.5 g/cm³).
V - volume of the magnet (in cm³ or m³).
For a magnet with a typical density of 7.5 g/cm³ and a volume of 10 cm³, the weight is:
m = 7.5 × 10 = 75 g.
Knowing the weight is crucial in projects where balance between mass and magnetic force is important.
m = ρ × V, where:
m - mass of the magnet (in grams or kilograms).
ρ - density of the magnet (typically 7.5 g/cm³).
V - volume of the magnet (in cm³ or m³).
For a magnet with a typical density of 7.5 g/cm³ and a volume of 10 cm³, the weight is:
m = 7.5 × 10 = 75 g.
Knowing the weight is crucial in projects where balance between mass and magnetic force is important.