Gravitational field strength is a mechanism for measuring gravity. It shows the magnitude of gravity at a particular place.
Gravitational field strength is a vector quantity consisting of direction as well as magnitude.
Is gravitational field strength a vector ? Yes, it is, as its formula is gravitational force per unit mass. As gravitational field strength consists of force, and as force is a vector quantity, it naturally makes it a vector quantity.
A scalar quantitywill only have magnitude, i.e. a number. For example – 25 metres. It is always one-dimensional.
A vector quantitywill have magnitude as well as direction. For example – 25 metres, north. It is multi-dimensional.
What is Gravity?
Gravity is expressed as the force of attraction between any two objects in the universe. It is the weakest force in the universe and has no specific range.
The gravitational force is enormous when the object is heavier. Thus, always the lighter object will be attracted towards the heavier object. Due to this reason, the Earth orbits around the sun, and moon around the Earth.
The exciting fact about gravitation is that all the objects in this universe have their own gravitational field, including humans!
Yes! You read it correctly. But, as gravity is the weakest force, all other gravitation fields are negligible compared to the earth’s gravitational force or, in fact, weaker than any other planet’s gravitational force.
For comparing a human’s gravitational field to that of the Earth’s gravitational field, let us take an example. Say, person A is standing one meter away from person B, who weighs 100 Kg. Earth’s gravitational acceleration will be 1.5 billion times larger than the gravitational acceleration of person B. That is why person A will not gravitate to person B.
Another critical subject heavily affected by gravity is mass and weight. Mass is the quantity of matter available in an object, while weight is the outcome of the force of gravity acting on it. Mass multiplied by gravity gives weight.
w = m x gWhere, w = Weight g = Gravitational Field Strength or Gravitational Acceleration m = Mass of the object
Gravity is one of the four elemental forces of nature. Gravity affects the solar system or, in fact, any system in the universe. The formation of stars, planets, asteroids, etc., all depends on gravity.
Various scientists like Robert Hooke, Galileo Galilei, Jesuits Grimaldi, Riccioli, Bullialdus, Borelli, etc., put forward different theories on gravitation, and some of which are very similar to each other but still not entirely practically proven. Ancient Greek Philosophers like Archimedes, Roman architect and engineer – Vitruvius, Indian mathematicians and astronomers like Aryabhatta and Brahmagupta also identified Gravity.
But then, one fine day, an apple fell upon Sir Isaac Newton, and he derived the “Newton’s Law of Universal Gravitation” and the world followed it. According to Newton’s theory, the gravitational force is directly proportional to the product of masses and inversely proportional to the square of the distance between them.
The equation for gravitational force is given as:
Fα(m1m2)/r2
To remove the proportionality sign, a constant is added. In this scenario, it is the gravitational constant “G”.
F=G*(m1m2)/r2Where, F = Gravitational Force G = Gravitational Constant = 6.674 x 10-11 N.m2.kg-2 m1 = Mass of the object 1 m2 = Mass of the object 2 r = Distance between the centre of the objects
Read more on Is Gravity an External Force
Why is Gravitational Force a Vector Quantity?
Gravitational field strength is a physical quantity according to classical mechanics.
Gravitational field strength is denoted by ‘g’, and its formula is given as force per unit mass.
g=F/mWhere, g = Gravitational Field Strength F = Gravitational Force m = Mass of the Object
According to this formula, the S. I. Unit of g is N/Kg, and earth’s gravitational field strength is 10 N/Kg. “g” is also referred to as the Gravitational Acceleration, given as 9.8 m/s2 for earth.
As force is a vector quantity, gravitational force will be a vector quantity, making gravitational field strength a vector quantity.
Albert Einstein also put forward his theory for gravitation in his general theory of relativity, and it also has superseded Newton’s theory. Still, it is only used when there is the requirement for extreme accuracy or when dealing with a powerful gravitational field near a super-massive and extremely dense object like the black hole.
The bending of space-time is a tricky concept, but it is explained in the general theory of relativity given by Albert Einstein. Here, we only need to understand that it involves the 3-dimensional space and 1-dimensional time, and thus, it is a 4-dimensional flow. So, due to gravity, there is a change in the space-time flow, resulting in different perceptions of observations of an event from different places or observers.
Read more on Is Gravity a Conservative Force
Comparison of Gravitational Acceleration on different planets of our Solar System.
Gravitational acceleration is the speed at which the planet pulls a body. For Earth, its value is 9.8 m / s2. Let’s try to find the acceleration due to gravitation on different planets present in our solar system.
One can detect the gravitational acceleration of any planet using the formula:
g=Gm/r2Where, g = Gravitational Acceleration G = Gravitational Constant = 6.674 x 10-11 N. m2. kg-2 (it will be same everywhere) r = radius of the planet m = Mass of the Planet
- Gravitational acceleration on Mercury
| For Mercury, | g = ? |
| G = 6.674 x 10-11 N. m2. kg-2 | |
| r = ~2.4 x 106 m | |
| m = 3.28 x 1023 Kg |
Putting all this information in the formula, we get:
g = 3.61 m / s2
- Gravitational Acceleration on Venus
| For Venus, | g = ? |
| G = 6.674 x 10-11 N. m2. kg-2 | |
| r = ~6.07 x 106 m | |
| m = 4.86 x 1024 Kg |
Putting all this information in the formula, we get:
g = 8.83 m / s2
- Gravitational Acceleration on Mars
| For Mars, | g = ? |
| G = 6.674 x 10-11 N. m2. kg-2 | |
| r = ~3.38 x 106 m | |
| m = 6.42 x 1023 Kg |
Putting all this information in the formula, we get:
g = 3.75 m / s2
- Gravitational Acceleration on Jupiter
| For Jupiter, | g = ? |
| G = 6.674 x 10-11 N. m2. kg-2 | |
| r = ~6.98 x 107 m | |
| m = 1.90 x 1027 Kg |
Putting all this information in the formula, we get:
g = 26.0 m / s2
- Gravitational Acceleration on Saturn
| For Saturn, | g = ? |
| G = 6.674 x 10-11 N. m2. kg-2 | |
| r = ~5.82 x 107 m | |
| m = 5.68 x 1026 Kg |
Putting all this information in the formula, we get:
g = 11.2 m / s2
- Gravitational Acceleration on Uranus
| For Uranus, | g = ? |
| G = 6.674 x 10-11 N. m2. kg-2 | |
| r = ~2.35 x 107 m | |
| m = 8.68 x 1025 Kg |
Putting all this information in the formula, we get:
g = 10.5 m / s2
- Gravitational Acceleration on Neptune
| For Neptune, | g = ? |
| G = 6.674 x 10-11 N. m2. kg-2 | |
| r = ~ 2.27 x 107 m | |
| m = 1.03 x 1026 Kg |
Putting all this information in the formula, we get:
g = 13.3 m / s2
Gravitational Constant vs. Acceleration Gravity
There are innumerable and remarkable differences between the gravitational constant and acceleration gravity. It would be easy to study them in the tabular format.Gravitational Constant Acceleration Gravity It is an empirical physical constant. Acceleration due to gravity on an object under free fall (generally in vacuum). Also known as “Newtonian Constant of Gravitation” or “Universal Gravitational Constant” or “Cavendish Gravitational Constant.” Also known as “Gravitational Field Strength”. Denoted by “G”. Denoted by “g”. The value of the gravitational constant is independent of all factors, and thus, remains the same throughout the universe. The value of acceleration gravity is different on different planets or any other astronomical object. It is proportionality constant, and thus, it would remain the same anywhere, be it the centre of a planet, outside of it, near the poles, in vacuum, etc., the value of G will remain as it is, without any change. The gravitational acceleration is maximum at the earth’s surface. Gravitational acceleration starts decreasing whether one moves in upward or downward direction. Gravitational constant is a scalar quantity. Acceleration gravitation is a vector quantity. Value of gravitational constant is never zero. Value of acceleration gravitation is zero at the centre of the earth. No formula for G. Formula for finding g = F/m The relation between G and g can be given as: G=gr2/m G = The relation between G and g can be given as: g = GM/r2 S. I. Unit of G = N. m2 / kg2 S. I. Unit of g = m / s2 G = 6.674 x 10-11 N. m2. kg-2 Value of gravitational acceleration for earth = g = 9.8 m / s2
FAQs
Is gravitational field strength a vector? ›
Gravitational fields are vector fields. They can be visualized in two ways - either by drawing an arrow representing the gravitational field vector at that point, or by drawing field lines. For more details, see Vector Fields.
Why is gravitational force a vector? ›Gravity and displacement are vectors. They have a value plus a direction. (In this case, their directions are down and down respectively) The reason we can get a scalar energy from vectors gravity and displacement is because, in this case, they happen to point in the same direction.
Is gravitational force a vector quantity True or false? ›It is a vector quantity. As we know, the scalar quantity only possesses magnitude, not direction, but gravity possesses both magnitudes and direction. So, as gravity 'g' possesses magnitude and direction, gravity is a force attractive in nature. The correct statement would be that gravity is a vector quantity.
Is the gravitational field a scalar or a vector? ›The S.I. unit of gravitational field intensity is N kg-1. The gravitational field intensity is a scalar quantity.
Is G force a vector quantity? ›Thus, a g-force is a vector of acceleration. It is an acceleration that must be produced by a mechanical force, and cannot be produced by simple gravitation.
What is vector form of gravitational field? ›g=−GMrr3 (point mass), where r is the position of the test point relative to the mass M. Note that we have written this equation in vector form, reflecting the fact that the gravitational field is a vector. Thus, r = xtest - xmass, where xtest and xmass are the position vectors of the test point and the mass M.
Is gravitational field strength a force? ›Gravitational field strength, g, is defined as the force per unit mass, g = F/m. From Newton's second law and the definition of the newton, free-fall acceleration, g, is also equal to the gravitational force per unit mass.
Is force a vector Why or why not? ›(Introduction to Mechanics) vector quantities are quantities that possess both magnitude and direction. A force has both magnitude and direction, therefore: Force is a vector quantity; its units are newtons, N.
What is gravitational field strength in simple words? ›Gravitational field strength (g) is measured in newtons per kilogram (N/kg). The Earth's gravitational field strength is 9.8 N/kg. This means that for each kg of mass, an object will experience 9.8 N of force. Where there is a weaker gravitational field, the weight of an object is smaller.
What does gravitational field strength depend on? ›The gravitational field strength g depends only on the mass of the body M causing the field. Hence, objects with any mass m in that field will experience the same gravitational field strength. The gravitational field strength g is inversely proportional to the square of the radial distance, r.
Is gravitational field strength the same as gravity? ›
Gravitational field strength (g)
All objects are attracted towards each other by a force called gravity. Gravitational field strength is a measure of the force of gravity, measured in Newtons (N), exerted per kilogram (kg) mass of substance. The units for gravitational field strength are N/kg.
- (i) Gravitational Forces are always forces of attraction,
- (ii) Every force is formed as an action-reaction pair, that means, the forces exerted by two bodies on each other are equal in magnitude but opposite in direction,
A force applied to a particle is also a vector as it has both a magnitude and a direction. We can use the formula F=ma F = m a , where m is the mass of the particle, to solve problems about force. If a particle is resting in equilibrium then the resultant of all the forces acting on it is zero.
What is the value of g as a vector? ›Its value is 9.8 m/s2 on Earth.
Is force a vector quantity yes or no? ›Force is a vector quantity, displacement is also a vector quantity.
Is gravitational field strength a force or acceleration? ›Gravitational field strength, g, is defined as the force per unit mass, g = F/m. From Newton's second law and the definition of the newton, free-fall acceleration, g, is also equal to the gravitational force per unit mass.
What is the difference between scalar and vector? ›Vector quantities have two characteristics, a magnitude and a direction. Scalar quantities have only a magnitude. When comparing two vector quantities of the same type, you have to compare both the magnitude and the direction. For scalars, you only have to compare the magnitude.
Is force a vector that is right? ›Answer: True, force is a vector quantity that has both magnitude and direction.
What are 5 examples of a vector quantities? ›Other examples of vector quantities are displacement, acceleration, force, momentum, weight, the velocity of light, a gravitational field, current, and so on.
Why is gravitational field strength constant? ›Acceleration. This shows that the gravitational field strength is also the acceleration due to gravity on any object. This acceleration is the same for any object, regardless of mass. When considering small heights above the Earth's surface, such as those in our day-to-day experiences, g remains roughly constant.
What is another name for gravitational field strength? ›
The most common other name used for gravitational force is simply gravity.
Where is gravitational field strength the strongest? ›The earth is an oblate spheroid, and that means it bulges out in the middle (the equator). That also means the poles end up a little closer to the centre of gravity. That is why on the surface of earth, at the poles the intensity of gravity is the maximum.
What two factors determine the strength of a gravitational field? ›Gravity is affected by the size of an object and the distance between the objects. When the mass of an object increases the force of gravity increases as well.
Does gravitational field strength change with mass? ›The size of the gravitational force is proportional to the masses of the objects and weakens as the distance between them increases.
Is gravitational field strength the same everywhere? ›Gravity is often assumed to be the same everywhere on Earth, but it varies because the planet is not perfectly spherical or uniformly dense. In addition, gravity is weaker at the equator due to centrifugal forces produced by the planet's rotation.
Is gravitational field strength the same everywhere on Earth? ›While the Earth has an average gravitational force, different locations on Earth have gravitational forces that are larger or smaller than average. This is because each location has more or less mass than the average. Gravity is a physical force of attraction between objects.
Does gravitational field strength depend on distance? ›The force of gravity depends directly upon the masses of the two objects, and inversely on the square of the distance between them. This means that the force of gravity increases with mass, but decreases with increasing distance between objects.
Is gravitational field strength a unit? ›Gravitational field strength (g) is measured in newtons per kilogram (N/kg). The Earth's gravitational field strength at, or close to, the surface is 10 N/kg. This means that for each kilogram of mass, an object will experience 10 N of force.
Is strength of the electric field a scalar or vector? ›Electric field is a vector quantity since force is a vector quantity.
What is the formula for the gravitational field strength vector? ›g=−GMrr3 (point mass), where r is the position of the test point relative to the mass M. Note that we have written this equation in vector form, reflecting the fact that the gravitational field is a vector. Thus, r = xtest - xmass, where xtest and xmass are the position vectors of the test point and the mass M.
Is gravitational field strength always the same? ›
Acceleration. This shows that the gravitational field strength is also the acceleration due to gravity on any object. This acceleration is the same for any object, regardless of mass. When considering small heights above the Earth's surface, such as those in our day-to-day experiences, g remains roughly constant.
Is electric field a vector or vector? ›Since the force is a vector, the electric field is also a vector.
Is magnetic field strength a vector? ›The magnetic field is described mathematically as a vector field. This vector field can be plotted directly as a set of many vectors drawn on a grid. Each vector points in the direction that a compass would point and has length dependent on the strength of the magnetic force.
Is magnetic field strength a vector quantity? ›Magnetic force is a vector quantity as it has a magnitude and direction both. It either attracts or repels depending upon the polarity of both are magnets.
What is an example of gravitational field strength? ›Planets feature different values of gravitational field strength on their surfaces due to variations in their mass and radius. For example, the gravitational field strength on the surface of Earth is 9.81 m/s², while the gravitational field strength on the surface of Mars is only 3.71 m/s².