The acceleration felt by a free-falling object due to the gravitational force of the mass body is called gravitational acceleration. It is denoted by g and calculated using SI unit m/s2. The value of g depends on the mass of the body and its size. Its value varies from body to body. In this article, we will learn about the value of g in physics in detail.
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Acceleration due to Gravity on Earth
Acceleration due to gravity on Earth is a measure of how quickly objects fall towards the ground when dropped. It is a constant value, which is equal to 9.81 m/s² approximately. This means that any object falling freely under gravity's influence accelerates downward at this rate every second.
- While 9.81 m/s² is the average, the exact value can vary slightly. This variation depends on altitude and the Earth's shape.
- Gravity acts on all objects equally, regardless of their mass. This is why a feather and a hammer will hit the ground at the same time in a vacuum.
- Gravity is slightly stronger at the poles than at the equator. This is due to the Earth's slight bulge at the equator.
- The force of gravity on an object determines its weight. More gravity means more weight.
- Gravity holds Earth’s atmosphere in place, protecting us from the vacuum of space.
Value of g
The value of g varies across different planets and satellites due to differences in mass and radius. This variation is important for understanding the gravitational forces on different celestial bodies. It influences everything from the weight of objects to the behavior of their atmospheres.
Here is a list of values of g on various planets and satellites in the solar system :
| Celestial Body | Value of g (m/s2) |
|---|---|
| Mercury | 3.7 |
| Venus | 8.87 |
| Earth | 9.81 |
| Moon | 1.62 |
| Mars | 3.71 |
| Jupiter | 24.79 |
| Saturn | 10.44 |
| Uranus | 8.69 |
| Neptune | 11.15 |
| Pluto | 0.62 |
Calculation of Acceleration due to Gravity on Earth
From Newton's law of universal gravitation,
Acceleration due to gravity, g = (G ×M)/r2
Here, G is the gravitational constant, M is the mass of the Earth, and r is the radius of the Earth.
We know,
G = 6.674×10-11 m3/kg/s2
M = 5.972 × 1024 kg
r = 6.371 × 106m
Putting these values into the formula to calculate g, we have :
g = {(6.674 × 10-11) × (5.972×1024)}/ (6.371 × 106)2
This calculation gives the value of g as approximately 9.81 m/s².
Conclusion
In conclusion, the value of g in physics changes based on location. It measures the acceleration due to gravity. On Earth, its value is about 9.8 m/s². However, g differs on other planets and moons. The value of g is very useful for scientific and engineering calculations. It influences everything from weight measurements to the orbits of satellites. Thus, g is fundamental in both theoretical and applied physics.
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