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A slender rod with length L has a mass per unit length that varies with distance from the left-hand end, where x=0, according to dm/dx = (gamma)x, where (gamma) has units of kg/m^2.
I calculated the total mass of the rod by integrating. I got
M = 0.5(gamma)L^2
In the second part I found the moment of inertia with the axis of rotation to be at x=0, perpendicular to the rod. I don't know how to represent the integration symbol, so I'll use "|." I am integrating from 0 to L
I = |r^2dm
I = |L^2(gamma)L = (gamma)|L^3 = [(gamma)L^4]/4
= [2M/L^2][0.25L^4] = 0.5ML^2
The third part asks me to do the same thing for the rod, this time with the axis of rotation at the opposite end of the rod. I know I have to integrate from L to 0, but shouldn't this just give me the negative of my previous expression? I know it's wrong, but I don't know how the mass expression changes at the other end. Can someone help?
I calculated the total mass of the rod by integrating. I got
M = 0.5(gamma)L^2
In the second part I found the moment of inertia with the axis of rotation to be at x=0, perpendicular to the rod. I don't know how to represent the integration symbol, so I'll use "|." I am integrating from 0 to L
I = |r^2dm
I = |L^2(gamma)L = (gamma)|L^3 = [(gamma)L^4]/4
= [2M/L^2][0.25L^4] = 0.5ML^2
The third part asks me to do the same thing for the rod, this time with the axis of rotation at the opposite end of the rod. I know I have to integrate from L to 0, but shouldn't this just give me the negative of my previous expression? I know it's wrong, but I don't know how the mass expression changes at the other end. Can someone help?