NEET | 2016Center of MassHard

Question

Two identical charged spheres suspended from a common point by two massless strings of lengths 𝑙, areinitially at a distance d(d< < 𝑙) apart because of their mutual repulsion. The charges begin to leak fromboth the spheres at a constant rate. As a result, the spheres approach each other with a velocity υ. Then υvaries as a function of the distance 𝑥 between the spheres, as

Options

A.

υ ∝ x12

B.

υ∝x

C.

υ∝ x-12

D.

υ ∝x-1

Solution


θ=x2l
fe cos θ = mgh λθ
fe = mg. (x/2)
kq2x2=mgx2e
kq2 = mg2lx3
q ∝ x32
dqdt∝32x12.dxdt
⇒ x12. v = constant
v∝ x-12

Create a free account to view solution

View Solution Free
Topic: Center of Mass·Practice all Center of Mass questions

More Center of Mass Questions

Two wires of same metal have the same length but their cross sections are Anthe ratio 3 : 1. They are joined in series. ...A uniform rope of linear mass density &#955; and length l is coiled on a smooth horizontal surface. One end is pulled up...Two blocks of mass 3 kg and 6 kg respectively are placed on a smooth horizontal surface. They are connected by a light s...A wagon filled with sand has a hole so that sand leaks through the bottom at a constant rate &#955;. An external force a...The centre of mass of a system of particles is at the origin. From this we conclude that...