Constants and Trigonometry
A constant in an equation always has the same value. For example the speed of light, Planck's constant are all examples of constants that are used in science. Trigonometry is the relationship between the angles and sides of right angled triangles. Trigonometri...
Constants in Equations
A constant in an equation always has the same value. For example the speed of light (\(c=\text{2.99} \times \text{10}^{\text{8}}\text{ m·s$^{-1}$}\), Planck's constant (\(h\)) and Avogadro's number (\({N}_{A}\)) are all examples of constants that are used in science. The following table lists some of the constants you will encounter.
Constant |
Symbol |
Value and Units |
SI Units |
|
Atomic mass unit |
u |
\(\text{1.67} \times \text{10}^{-\text{24}}\) \(\text{g}\) |
\(\text{1.67} \times \text{10}^{-\text{27}}\) \(\text{kg}\) |
|
Charge on an electron |
e |
\(-\text{1.6} \times \text{10}^{-\text{19}}\) \(\text{C}\) |
\(-\text{1.6} \times \text{10}^{-\text{19}}\) \(\text{s·A}\) |
|
Speed of sound (in air, at \(\text{25}\) \(\text{℃}\)) |
\(\text{344}\) \(\text{m·s$^{-1}$}\) |
||
|
Speed of light |
c |
\(\text{3} \times \text{10}^{\text{8}}\) \(\text{m·s$^{-1}$}\) |
|
|
Planck's constant |
h |
\(\text{6.626} \times \text{10}^{-\text{34}}\) \(\text{J}\) |
\(\text{6.626} \times \text{10}^{-\text{34}}\) \(\text{kg·m$^{2}$·s$^{-1}$}\) |
|
Avogadro's number |
\({N}_{A}\) |
\(\text{6.022} \times \text{10}^{\text{23}}\) |
|
|
Gravitational acceleration |
g |
\(\text{9.8}\) \(\text{m·s$^{-1}$}\) |
|
Trigonometry
Trigonometry is the relationship between the angles and sides of right angled triangles. Trigonometrical relationships are ratios and therefore have no units. You should know the following trigonometric ratios:
Sine
This is defined as \(\sin A = \frac{\text{opposite}}{\text{hypotenuse}}\)
Cosine
This is defined as \(\cos A = \frac{\text{adjacent}}{\text{hypotenuse}}\)
Tangent
This is defined as \(\tan A = \frac{\text{opposite}}{\text{adjacent}}\)
This lesson is part of:
Skills for Science