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I'm a theoretical physicist.


55m
revised Lagrangian $L' = L + \frac{df}{dt}$ gives the same equations of motion
Thanks JamalS for edit. Removes indices since OP doesn't have them
1h
reviewed Leave Closed A Question on Friction
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answered Lagrangian $L' = L + \frac{df}{dt}$ gives the same equations of motion
2h
revised Deriving the energy-momentum tensor conservation equation in complex coordinates, Polchinski 2.4.2
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2h
revised Could the 6 extra dimensions in superstring theory be a product of two manifolds?
Added explanation
3h
comment Lagrangian $L' = L + \frac{df}{dt}$ gives the same equations of motion
Since $\frac{df}{dt}= \frac{\partial f}{\partial q}\dot{q} + \frac{\partial f}{\partial t}$ is an identity (via the chain rule), one is free to use any of the two forms one would like. They are equivalent. Related: physics.stackexchange.com/q/174137/2451 , physics.stackexchange.com/q/87628/2451 and links therein.
3h
revised A Question on Friction
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3h
comment What are the units of the creation and annihilation operators?
Possible duplicates: physics.stackexchange.com/q/11500/2451 and links therein.
3h
revised Simple Harmonic Motion - What are the units for $\omega_0$?
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3h
revised What are the units of the creation and annihilation operators?
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3h
revised Invariance of Fermionic action under Lorentz transformations
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6h
comment Tethered vs Liquid membrane
$\uparrow$ Which books?
6h
reviewed Leave Closed Tethered vs Liquid membrane
7h
revised Initial position and velocity given, force given. Find the trajectory of the particle
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8h
revised Acceleration of a system
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8h
revised Pendulum at an angle
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8h
revised Determing Velocity of Moons
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8h
comment Ladder Operator proof
This question (v2) about the possible spectrum of a SHO is answered in many textbooks. See e.g. this Phys.SE post and link therein.
8h
comment Mathematics of simplified air resistance
Suggestion to the question (v2): Replace mass $m$ with $1/m$, because a heavier ball is less affected by drag.
8h
revised Mathematics of simplified air resistance
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