# How do scientists know the mass of star or planet

## How do scientists know the mass of stars?

The

**masses of stars**can be determined by analysis of the orbit of binary**stars**—two**stars**that orbit a common center of**mass**. In visual binaries, the two**stars**can be seen separately in a telescope, whereas in a spectroscopic binary, only the spectrum reveals the presence of two**stars**.## How do scientist measure the mass of planets?

The most accurate way of

**measuring the mass**of a**planet**is**to**send a spacecraft**to**it and**measure**the acceleration due**to**gravity as the spacecraft passes by it. Alternatively, if the**planet**has a moon then its**mass**can be calculated from the moon’s orbit.## What is the heaviest planet?

Fifth in line from the Sun, Jupiter is, by far, the largest

**planet**in the solar system – more than twice as massive as all the other**planets**combined.## What is the G in physics?

In the first equation above,

**g**is referred to as the acceleration of gravity. Its value is 9.8 m/s^{2}on Earth. That is to say, the acceleration of gravity on the surface of the earth at sea level is 9.8 m/s^{2}. When discussing the acceleration of gravity, it was mentioned that the value of**g**is dependent upon location.## How many G’s can kill you?

Changes in speed are expressed in multiples of gravitational acceleration, or ‘

**G**‘. Most of us**can**withstand up to 4-6G. Fighter pilots**can**manage up to about 9G for a second or two. But sustained**G**-forces of even 6G**would**be fatal.## Why is gravity 9.81 ms 2?

In SI units, G has the value 6.67 × 10

^{–}^{11}Newtons kg^{–}**m**^{2}**. The acceleration g=F/m**^{2}_{1}due to**gravity**on the Earth can be calculated by substituting the mass and radii of the Earth into the above equation and hence g=**9.81 m s**^{–}**.**^{2}## What is value of g’on Earth?

we multiply the

**Gravitational constant G**= 6.673X10^-11 by the**earth’s**mass divided by the**earth’s**radius which will give us F/m2 = acceleration derived from the formula F = ma.## What does 9.81 mean?

It has an approximate value of

**9.81**m/s2, which**means**that, ignoring the effects of air resistance, the speed of an object falling freely near the Earth’s surface will increase by about**9.81**metres (32.2 ft) per second every second.## Where is gravity strongest on earth?

The effect of

**Earth’s gravity**is**stronger**, the closer you are to the centre of**gravity**, roughly the centre of the**earth**. So the**gravitational**effect will be slightly weaker at the equator than at the poles. And of course at the top of a mountain on/near the equator, slightly weaker again.## What is G called?

G is called

**Universal Gravitation Constant**because its value i.e. 6.67 x 10^{–}^{11}Nm^{2}kg^{–}^{2}is constant thought the universe.## Why is G called a universal constant class 9?

**G**is

**called universal constant**becuase its value remains the same throughout the universe and is independent of masses of the objects. Answer: Capital

**G**will be

**constant**become the value of the

**G**will be

**constant**anywhere in the Universe.

## How was g calculated?

The value of

**G**was not experimentally**determined**until nearly a century later (1798) by Lord Henry Cavendish using a torsion balance. Once the torsional force balanced the gravitational force, the rod and spheres came to rest and Cavendish was able to determine the gravitational force of attraction between the masses.## Why is G universal?

**G**is called the

**universal**gravitational constant because its value is constant and doesn’t change from place to place. which is 6.673 × 10^-11 Nm^2/kg^2. this law is

**universal**in the sense that it is applicable to all the bodies whether the bodies are big or small whether they are celestial or terrestrial.

## Why value of g is constant?

The force of attraction between any two unit masses separated by a unit distance is called universal

**gravitational constant**denoted by**G**measured in Nm^{2}/kg^{2}. The**value**of the**gravitational constant**is the same throughout the universe. The**value of G**is different from**g**, which denotes the acceleration due to**gravity**.## What is small G?

**small g**is acceleration due to gravity while big

**G**is a gravitational constant. The acceleration which is gained by an object becauseof the gravitational force is called its acceleration due to gravity.

## What is the difference between G and G?

**g**is the gravitational force exerted by any planet. For earth it’s 9.8m/s2.

**G**can be

**g**but

**g**cannot be

**G**.

question_answer Answers(5)

Acceleration due to gravity ( g ) | Universal Gravitation Constant ( G ) |
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Value of g=9.8 m/s^{2} | Value of G=6.673×10-11 Nm^{2}/kg^{2} |

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Sep 20, 2013

## What is relation between G and G Class 9?

The acceleration on an object due to the

**gravity**of any massive body is represented by**g**(small**g**). The force of attraction**between**any two unit masses separated by unit distance is called universal gravitational constant denoted by**G**(capital**G**).## What is the difference between G and G in gravitation Class 9?

At Earth’s surface, the acceleration of

**gravity**is 9.8 ms^{–}^{2}. Thus, for every second an object is in free fall, its speed increases by about 9.8 metres per second. The acceleration due to Earth’s**gravity**is denoted by the symbol ‘**g**. ‘PHYSICS Related Links | |
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