- #1
twowheelsbg
- 25
- 0
Homework Statement
In a two-dimensional space there is a system of two bodies,
masses M1, M2, and coordinates (X1,Z1) and (X2,Z2)
I have to find total mass, its coordinates, inertia momentum, and angular momentum
Homework Equations
... my memories help here, obviously not so good ...
The Attempt at a Solution
total mass M=M1+M2
coordinates X=(X1*M1+X2*M2)/(M1+M2)
Z=(Z1*M1+Z2*M2)/(M1+M2)
Inertia momentum
first i calculate radius vectors R1=sqrt(X1*X1+Z1*Z1)
R2=sqrt(X2*X2+Z2*Z2)
then inertia momentums I1=M1*R1*R1
I2=M2*R2*R2,
and total inertia momentum I=I1+I2,
and here I tried to recheck my result other way:
common radius as R=sqrt(X*X+Z*Z), and inertia as I=(M1+M2)*R*R,
but the result was different which puzzled me ...
I am more close to first approach, but why second is not correct ?
Last edited: