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  2. Duty cycle - Wikipedia

    en.wikipedia.org/wiki/Duty_cycle

    As a formula, a duty cycle (%) may be expressed as: [2] Equally, a duty cycle (ratio) may be expressed as: where is the duty cycle, is the pulse width (pulse active time), and is the total period of the signal. Thus, a 60% duty cycle means the signal is on 60% of the time but off 40% of the time.

  3. Speed of light - Wikipedia

    en.wikipedia.org/wiki/Speed_of_Light

    v. t. e. The speed of light in vacuum, commonly denoted c, is a universal physical constant that is exactly equal to 299,792,458 metres per second (approximately 300,000 kilometres per second; 186,000 miles per second; 671 million miles per hour).

  4. Half-life - Wikipedia

    en.wikipedia.org/wiki/Half-life

    For three or more processes, the analogous formula is: 1 T 1 / 2 = 1 t 1 + 1 t 2 + 1 t 3 + ⋯ {\displaystyle {\frac {1}{T_{1/2}}}={\frac {1}{t_{1}}}+{\frac {1}{t_{2}}}+{\frac {1}{t_{3}}}+\cdots } For a proof of these formulas, see Exponential decay § Decay by two or more processes .

  5. Black-body radiation - Wikipedia

    en.wikipedia.org/wiki/Black-body_radiation

    The law was formulated by Josef Stefan in 1879 and later derived by Ludwig Boltzmann. The formula E = σT 4 is given, where E is the radiant heat emitted from a unit of area per unit time, T is the absolute temperature, and σ = 5.670 367 × 10 −8 W·m −2 ⋅K −4 is the Stefan–Boltzmann constant. Equations

  6. Equations for a falling body - Wikipedia

    en.wikipedia.org/wiki/Equations_for_a_falling_body

    The first equation shows that, after one second, an object will have fallen a distance of 1/2 × 9.8 × 1 2 = 4.9 m. After two seconds it will have fallen 1/2 × 9.8 × 2 2 = 19.6 m; and so on. The next-to-last equation becomes grossly inaccurate at great distances. If an object fell 10 000 m to Earth, then the results of both equations differ ...

  7. Equations of motion - Wikipedia

    en.wikipedia.org/wiki/Equations_of_motion

    In elementary physics the same formulae are frequently written in different notation as: v = u + a t [ 1 ] s = u t + 1 2 a t 2 [ 2 ] s = 1 2 ( u + v ) t [ 3 ] v 2 = u 2 + 2 a s [ 4 ] s = v t − 1 2 a t 2 [ 5 ] {\displaystyle {\begin{aligned}v&=u+at&[1]\\s&=ut+{\tfrac {1}{2}}at^{2}&[2]\\s&={\tfrac {1}{2}}(u+v)t&[3]\\v^{2}&=u^{2}+2as&[4]\\s&=vt ...

  8. Torque - Wikipedia

    en.wikipedia.org/wiki/Torque

    This results in the formula changing to: P h p = τ l b f ⋅ f t ⋅ 2 π r a d / r e v ⋅ ν r e v / m i n 33 , 000 . {\displaystyle P_{\rm {hp}}={\frac {\tau _{\rm {lbf{\cdot }ft}}\cdot 2\pi _{\rm {rad/rev}}\cdot u _{\rm {rev/min}}}{33,000}}.}

  9. Cyclotron - Wikipedia

    en.wikipedia.org/wiki/Cyclotron

    Lawrence's 60-inch (152 cm) cyclotron, c. 1939, showing the beam of accelerated ions (likely protons or deuterons) exiting the machine and ionizing the surrounding air causing a blue glow. A cyclotron is a type of particle accelerator invented by Ernest Lawrence in 1929–1930 at the University of California, Berkeley, [1] [2] and patented in 1932.

  10. String theory - Wikipedia

    en.wikipedia.org/wiki/String_theory

    In physics, string theory is a theoretical framework in which the point-like particles of particle physics are replaced by one-dimensional objects called strings. String theory describes how these strings propagate through space and interact with each other. On distance scales larger than the string scale, a string looks just like an ordinary ...

  11. Tsiolkovsky rocket equation - Wikipedia

    en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation

    A rocket's required mass ratio as a function of effective exhaust velocity ratio. The classical rocket equation, or ideal rocket equation is a mathematical equation that describes the motion of vehicles that follow the basic principle of a rocket: a device that can apply acceleration to itself using thrust by expelling part of its mass with high velocity can thereby move due to the ...