magnetic sphere moving in iron dust; momentum related problem

mardi 1 octobre 2013

1. The problem statement, all variables and given/known data

A small magnetic sphere of initial mass Mo and initial radius Ro is moving through a space filled with iron dust. During its motion, 5% of displaced dust is deposited uniformly onto the surface of sphere. Given the density of dust to be ρ, find:

1. relation rate of increase in radius and velocity

2. if the magnet is moving under a force F=k(R^3), along the direction of motion, obtain a differential equation for radius at time t, when mass at time t, is much greater than it's initial mass and radius much greater that it's initial value

3. assuming a particular solution of differential equation to be R=b(t^2), find the value of acceleration of magnet ball at time t.



(b,k are constants)





2. Relevant equations

F(external)=0 => ΔP=0

dm/dt = 4∏ρ(R^2)dR







3. The attempt at a solution

couldn't solve any further than writing the above 2 equations






via Physics Forums RSS Feed http://www.physicsforums.com/showthread.php?t=713693&goto=newpost

0 commentaires:

Enregistrer un commentaire