# two particles with positive charges q1 and q2 and equal mass m are separated by a distance d.the lower one is at a distance h from ground and takes time t to fall and looses its charge after falling. find the time taken by upper charge to fall?

Arun Kumar IIT Delhi
8 years ago
Height of upper =h+d
lower =d

$g_{eff\,for\,lower}=(kq_1q_2/(d+x)^2+g) (-j)\\ g_{eff\,for\,upper\,until\, time \,t}=(-kq_1q_2/(d+x)^2+g) (-j) \\\\ apply\,vdv/ds=a\\ assuming\,v=0 \,at \,start\\ then\\ apply dx/dt=v \\\for \,both \,particle.$
with proper limits.

Thanks & Regards
Arun Kumar
IIT Delhi