Home
Class 12
PHYSICS
Two small balls A and B of positive char...

Two small balls A and B of positive charge Q each and masses m and 2m, respectively, are connected by a nonconducting light rod of length L. This system is released in a uniform electric field of strength E as shown. Just after the release (assume no other force acts on the system)

A

rod has angular acceleration `QE//2mL` in anticlockwise direction.

B

rod has angular acceleration `QE//2mL` in anticlockwise direction

C

acceleration of point A is `2QE//3m` toward right

D

acceleration of point A is `QE//m` toward right .

Text Solution

Verified by Experts

The correct Answer is:
A, D
a.,d.
Resultant force on arrangement is `2QE`, thus acceleration of center of mass is given by `a_(c)=2QE//3m`.
Net torque on system is
`QE((2L)/(3))=QE((L)/(3))=[mxx(4L^(2))/(9)+2mxx(L^(2))/(9)]a`
`a=(QE)/(2mL` (clockwise)
From constraint equation, we get
`a_(A)=a_(c)+a((2L)/(3))`
`=(2QE)/(3m)+(QE)/(2mL)((2L)/(3))=(3QE)/(3m)=(QE)/(m)`
Promotional Banner

Similar Questions

Explore conceptually related problems

A charge of mass .m. charge .2e. is released from rest in a uniform electric field of strength .E.. The time taken by it to travel a distance .d. in the field is

A dipole is formed by two point charge -q and +q, each of mass m, and both the point charge are connected by a rod of length l and mass m. This dipole is placed in uniform electric field vec(E) If the dipole is disturbed by a small angle theta from stable equilibrium position, prove that its motion will be almost SHM. also find its time period.

A simple pendulum consists of a small sphere of mass m suspended by a thread of length l . the sphere carries a positive charge q . The pendulum is placed in a uniform electric field of strength E directed vertically upwards. With what period will the pendulum oscillate if the electrostatic force acting on the sphere is less than the gravitational force?

A particle of mass .m. and charge q is placed at rest in a uniform electric field E and then released. The K.E. attained by the particle after moving a distance y is

A simple pendulum consists of a small sphere of mass m suspended by a thread of length l . the sphere carries a positive charge q . The pendulum is placed in a uniform electric field of strength E directed vertically upwards. With what period will pendulum oscillate if the electrostatic force acting on the sphere is less than the gravitational force ?

Two identical balls , each having a charge q and mass m , are suspended from a common point by two insultating strings each of length L . The balls are held at a separation x and then released. Find (a) the electric force on each ball (b) the component of the resultant force on a ball along and perpendicular to string (c ) the tension in the string (d) the acceleration of one of the balls. Consider the situation only for the instant just after the release.

A small ball of masss m and charge +q tied with a string of length l, rotating in a veticle circle under gravity and a uniform horizontal electric field E as shown. The tension in the string will be minimum for

Two point masses m and 4m are connected by a light rigid rod of length l at the opposite ends. Moment of inertia of the system about an axis perpendicular to the length and passing through the centre of mass is

A thin homogeneous rod of mass m and length l is free to rotate in vertical plane about a horizontal axle pivoted at one end of the rod. A small ballof mass m and charge q is attached to the opposite end of this rod. The whole system is positioned in a horizontal electric field of magnitude E=(mg)/(2q) . The rod is released from, shown position from rest. What is the speed of ball when rod becomes vertical?

Two uniform solid of masses m_(1) and m_(2) and radii r_(1) and r_(2) respectively, are connected at the ends of a uniform rod of length l and mass m . Find the moment of inertia of the system about an axis perpendicular to the rod and passing through a point at a distance of a from the centre of mass of the rod as shown in figure.