IIT JEE , AIEEE Forum - Physics , Mechanics

vpunithreddy

a sphere is moving with a velocity 'v' and rolling with a angular velocity

it will have a head on elastic collission with an other ball of same mass m

then

a)the first sphere comes to rest but keeps on rolling with angular velocity

b)the first sphere comes to rest and angular velocity becomes 0

c)the second sphere moves with velocity v but its angular velocity is o

d)the second sphere moves with velocity v and angular velocity

(neglect friction b/n the surfaces of spheres)

cvramana

In the choices the word rolling should be replaced by spinning.

It is not clear whether the floor is rough or smooth.

Considering smooth and since there is no friction between the spheres and the collision being elastic and the masses being equal they will interchange their linear velocity and the first body keeps spinning with the same angular velocity.

Therefore the answers A and C are correct.

neeraj

( a , c ) is the correct answer

There is a exchange of linear velocities. However the sphere and ball cannot exert torques on each other, as their surfaces are frictionless and the angular velocities of the spheres do not change. Hence sphere will stop moving but continue to rotate with an angular velocity w and ball will move with a speed v without rotating.

Therefore the answer is (a, c)

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