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

A ball of mass &#8242;m&#8242;, moving with uniform speed, collides elastically with another stationary ball. The incide...A stationary body explodes into four identical fragments such that three of them fly off mutually perpendicular to each ...The area of F-t curve is A, where &#8242;F&#8242; is the force on one mass due to the other. If one of the colliding bod...Three-man A, B &amp; C of mass 40 kg, 50 kg &amp; 60 kg are standing on a plank of mass 90 kg, which is kept on a smooth...Lower surface of a plank is rough and lying at rest on a rough horizontal surface. Upper surface of the plank is smooth ...