displace the charge q upwards it will not be back ...it will go upwards...
and if u dispace it downwards then it will be towards mean position but will not stop and move upwars further ...thus...unstable equilibrium....
1)a simple pendulum consists of a small sphere of mass m , has length l, carries chargeQ. It is placed in a uniform electric field E directed vertically upwards.will it execute SHH?What is its time period of oscillation.Pls exp with diagram if possible
2)A thin conducting wire ring of radius R has a charge +Q.What isthe increase in tension when a point charge +q is placed at its centre.
3)If we place a positive charge on the line perpendicular to the line joining two equal positive charges, would it be in an unstable equilibrium.Why? My dbt is if we displace it downwards then as the resultant is always upwards, it will go up towards its mean position
displace the charge q upwards it will not be back ...it will go upwards...
and if u dispace it downwards then it will be towards mean position but will not stop and move upwars further ...thus...unstable equilibrium....
find the 2nd question answer here:
http://lofi.forum.physorg.com/point-charge-and-line-charge-problem_7940.html
in the first question just put the downward force to be
mg-qE =F the time period should be
see if the pendulum is not displaced from its mean position and e.field is applied...then there will be no shm ....force acting on the bob will be...
f= qe + t - mg or f= mg-(qe+t)
and if it is displaced from its mean position at any angle then resolve qe and mg and equate the forces...to get results....