- #1
ubergewehr273
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Homework Statement
A uniform thin rod of length ##2l## and mass ##m## lies on a horizontal table. A horizontal impulse ##J## is given to the rod at one end. There is no friction. The total kinetic energy of the rod after impulse will be ?
Homework Equations
##Jl=I\omega##
##J=mv_{cm}##
##K=\frac {1} {2} mv^2_{cm} + \frac {1} {2} I_{cm}\omega^2##
The Attempt at a Solution
Using the 2nd equation it is evident that ##v_{cm}## is known. However while calculating ##\omega## after impulse is applied, my doubt is about which point are we supposed to conserve angular momentum? I get the answer while conserving about COM of rod but technically speaking doesn't impulse ##J## provide an external torque about the COM ? So, then about which point should we conserve angular momentum?