g is the acceleration of a freely falling body near Earth's surface. It falls with height (g′ = g(1 − 2h/R)) and depth (g′ = g(1 − d/R)), and is about 1/6 as much on the Moon.
Value of g in different units
| Value | Use it when |
|---|---|
| 9.8 m s⁻² | Standard value for numericals. |
| 10 m s⁻² | When the question says so, to keep numbers simple. |
| 9.80665 m s⁻² | Standard gravity, exact by definition. |
| 980 cm s⁻² | CGS. |
| 32.2 ft s⁻² | Imperial. |
Formulas that use g
- v = u + gt
- h = ut + ½gt²
- g = GM/R²
- T = 2π√(l/g)
Its dimensional formula is worked out on the dimensional formula of acceleration due to gravity g page.
Other constants
- Gas constant (R): 8.314 J mol⁻¹ K⁻¹
- Planck's constant (h): 6.626 × 10⁻³⁴ J s
- Avogadro's number (Nₐ): 6.022 × 10²³ mol⁻¹
- Speed of light (c): 3 × 10⁸ m/s
- Charge of an electron (e): 1.602 × 10⁻¹⁹ C
- Mass of an electron (mₑ): 9.109 × 10⁻³¹ kg
- Mass of a proton (mₚ): 1.673 × 10⁻²⁷ kg
- Mass of a neutron (mₙ): 1.675 × 10⁻²⁷ kg
- Universal gravitational constant (G): 6.674 × 10⁻¹¹ N m² kg⁻²
- Acceleration due to gravity (g): 9.8 m/s²
- Boltzmann constant (k): 1.381 × 10⁻²³ J/K
- Faraday constant (F): 96 485 C/mol
- Permittivity of free space (ε₀): 8.854 × 10⁻¹² C² N⁻¹ m⁻²
- Permeability of free space (μ₀): 4π × 10⁻⁷ T m/A
- Rydberg constant (R): 1.097 × 10⁷ m⁻¹
- Stefan–Boltzmann constant (σ): 5.67 × 10⁻⁸ W m⁻² K⁻⁴
- Wien's constant (b): 2.898 × 10⁻³ m K
- Bohr radius (a₀): 0.529 Å
- Molar volume of a gas at STP (Vₘ): 22.4 L/mol
The full list, searchable, is on the physical constants page.
Questions students ask
What is the value of acceleration due to gravity?
g = 9.8 m/s². In other units: 9.8 m s⁻²; 10 m s⁻²; 9.80665 m s⁻²; 980 cm s⁻²; 32.2 ft s⁻².
What is g in physics and chemistry?
g is the acceleration of a freely falling body near Earth's surface. It falls with height (g′ = g(1 − 2h/R)) and depth (g′ = g(1 − d/R)), and is about 1/6 as much on the Moon.
Which value of g should I use?
9.8 m s⁻²: Standard value for numericals. 10 m s⁻²: When the question says so, to keep numbers simple. 9.80665 m s⁻²: Standard gravity, exact by definition. 980 cm s⁻²: CGS. 32.2 ft s⁻²: Imperial.
What is the dimensional formula of acceleration due to gravity?
See the dimensional formula of acceleration due to gravity, worked out step by step on its own page.