Value of g in Physics: Overview, Questions, Preparation

Gravitation 2021

Vipra Shrivastava

Vipra ShrivastavaSenior Manager - Content

Updated on Aug 16, 2021 06:35 IST

The gravitational acceleration is experienced when an object falls from a height, and the external gravity acts on the object. The acceleration due to gravity is denoted as g and is measured using SI unit m/s2. The mass of an object and the radius determine the value of g, and it is different for the different objects.

Acceleration Due to Gravity

On earth, the acceleration due to gravity is 9.8 m/s2. It is determined by the mass of the earth and the radius of the earth. It also means that the velocity of an object falling will increase the acceleration by 9.8 every second. This acceleration occurs because of gravity on the earth.

Value of Gravity

The gravity of the different objects varies due to the different masses and radiuses of the objects. Let us take a look at the gravity of the planets:

Planets

Radius (m)

Mass (kg)

Value of g (m/s2)

Mercury

2.43 × 106

3.2 × 1023

3.61

Earth

6.4 × 106

6 × 1024

9.8

Venus

6.073 × 106

4.88 × 1024

8.83

Mars

3.38 × 106

6.42 × 1023

3.75

Jupiter

6.98 × 107

1.901 × 1027

26.0

Saturn

5.82 × 107

5.68 × 1026

11.2

Uranus

2.35 × 107

8.68 × 1025

10.5

Neptune

2.27 × 107

1.03 × 1026

13.3

Pluto

1.15 × 106

1.2 × 1022

0.61

From the above chart, we can say that the gravitational accelerations of all the planets is different from each other because of the difference in their radius and mass.

Calculation of the Acceleration due to gravity on Earth

The formula to calculate the acceleration due to gravity is g = GM / R2

Here, the gravitational constant is denoted as G,

The value of G is 6.674×10-11m3kg-1s-2.

Mass is denoted as M,

Radius as R, and acceleration due to gravity as g.

Mass of the earth = 6 × 1024

Radius = 6.4 × 106

By putting these values in the formula, we get,

g= 6.67 × 10-11 × 6 × 1024 / (6.4 × 106)2

So, the acceleration due to gravity on earth is 9.8 m/s2.

Illustrated Examples on Value of g in Physics

Example 1) Write the value of acceleration due to gravity on earth.

Answer – By solving the equation g= 6.67 × 10-11 × 6 × 1024 / (6.4 × 106)2

We will get the exact acceleration due to gravity, i.e., 9.8 m/s

Example 2) Write the formula to calculate the acceleration due to gravity.

Answer – The formula to calculate the acceleration due to gravity is g = GM / R2

Example 3) Write the acceleration due to the gravity of Jupiter and Saturn.

Answer – The acceleration due to the gravity of Jupiter and Saturn is 26.0 and 11.2, respectively.

FAQs on Value of g in Physics

Q: What do you mean by the acceleration due to gravity?

A: The acceleration due to gravity is experienced when an object falls from a height, and the external gravity applies to the object.

Q: What is the unit to measure the acceleration due to gravity?

A: The acceleration due to gravity is denoted as g and is measured using SI unit m/s 2

Q: What is the value of G?

A: The G is the gravitational constant, and the value of the gravitational constant is 6.674×10 -11m 3kg -1s -2.

Q: What is the acceleration due to gravity-dependent on?

A: The acceleration due to gravity is dependent on the mass and the radius of the object. The acceleration due to gravity is different for every object because it has a different mass and different radius.

Q: What is the radius and the mass of the planet Neptune?

A: The radius of Neptune is 2.27 × 10 7, and the mass of the Neptune is 1.03 × 10 26. The acceleration due to gravity is 13.3.

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