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Key Equations

PhysicsKey Equations

Key Equations

9.1 Work, Power, and the Work–Energy Theorem

equation for work

W = f d

force

f = w = m g

work equivalencies

W = P E_{e} = f m g

kinetic energy

K E = \frac{1}{2} m v^{2}

work–energy theorem

W = Δ KE = \frac{1}{2} m v_{2}^{2} - \frac{1}{2} m v_{1}^{2}

power

P = \frac{W}{t}

9.2 Mechanical Energy and Conservation of Energy

conservation of energy

K E_{1} + P E_{1} = K E_{2} + P E_{2}

9.3 Simple Machines

ideal mechanical advantage (general)

I M A = \frac{F_{r}}{F_{e}} = \frac{d_{e}}{d_{r}}

ideal mechanical advantage (lever)

I M A = \frac{L_{e}}{L_{r}}

ideal mechanical advantage (wheel and axle)

I M A = \frac{R}{r}

ideal mechanical advantage (inclined plane)

I M A = \frac{L}{h}

ideal mechanical advantage (wedge)

I M A = \frac{L}{t}

ideal mechanical advantage (pulley)

I M A = N

ideal mechanical advantage (screw)

I M A = \frac{2 π L}{P}

input work

W_{i} = F_{i} d_{i}

output work

W_{o} = F_{o} d_{o}

efficiency output

% efficiency = \frac{W_{o}}{W_{i}} \times 100

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- Authors: Paul Peter Urone, Roger Hinrichs
- Publisher/website: OpenStax
- Book title: Physics
- Publication date: Mar 26, 2020
- Location: Houston, Texas
- Book URL: https://openstax.org/books/physics/pages/1-introduction
- Section URL: https://openstax.org/books/physics/pages/9-key-equations

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