Total mass from mass distribution function

Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
2 replies · 2K views
noreally
Messages
7
Reaction score
0

Homework Statement



An obect whose mass is distributed according to function m(r)=m0e-r, for r ranging from 0 to ∞. Calculate total mass of the object. Write down and evaluate appropriate integral.

2. The attempt at a solution

well, I wasnt sure really how to start but thought it may be m(0) + m(∞) where m(0) would become just m0 leaving m0+ me-∞. Although i really have no idea.

This is part of a really strange module at my uni where there are no lectures and just a worksheet given out every other week with no guidance. :/

Thanks for any help!
 
Physics news on Phys.org
noreally said:

Homework Statement



An obect whose mass is distributed according to function m(r)=m0e-r, for r ranging from 0 to ∞. Calculate total mass of the object. Write down and evaluate appropriate integral.

2. The attempt at a solution

well, I wasnt sure really how to start but thought it may be m(0) + m(∞) where m(0) would become just m0 leaving m0+ me-∞. Although i really have no idea.

This is part of a really strange module at my uni where there are no lectures and just a worksheet given out every other week with no guidance. :/

Thanks for any help!

Do you see any symmetry in the mass distribution ?
 
Thanks for the reply, yes the object is symmetrical as the next part of the question is that its rotating about its symmetry axis r=0.