Two identical spheres move in opposite directions with speeds v1 and v2 and pass behind an opaque screen, where they may either cross without touching (event 1) or make an elastic head-on collision (event 2) -

Question

Two identical spheres move in opposite directions with speeds v1 and v2 and pass behind an opaque screen, where they may either cross without touching (event 1) or make an elastic head-on collision (event 2) - (A) we can never make out which event has occurred (B) we can not make out which event has occurred only if v1=v2 (C) we can always make out which event has occurred (D) we can make out which event has occurred only if v1=v2

Tardigrade Admin · Accepted Answer

Balls are identical and velocity exchanges if elastic head on collision occurs.

Q. Two identical spheres move in opposite directions with speeds $v_{1}$ and $v_{2}$ and pass behind an opaque screen, where they may either cross without touching (event 1) or make an elastic head-on collision (event 2) -

we can never make out which event has occurred

we can not make out which event has occurred only if $v_{1} = v_{2}$

we can always make out which event has occurred

we can make out which event has occurred only if $v_{1} = v_{2}$

Balls are identical and velocity exchanges if elastic head on collision occurs.

Q. Two identical spheres move in opposite directions with speeds v1​ and v2​ and pass behind an opaque screen, where they may either cross without touching (event 1) or make an elastic head-on collision (event 2) -

we can never make out which event has occurred

we can not make out which event has occurred only if v1​=v2​

we can always make out which event has occurred

we can make out which event has occurred only if v1​=v2​

Balls are identical and velocity exchanges if elastic head on collision occurs.

Q. Two identical spheres move in opposite directions with speeds $v_{1}$ and $v_{2}$ and pass behind an opaque screen, where they may either cross without touching (event 1) or make an elastic head-on collision (event 2) -

we can not make out which event has occurred only if $v_{1} = v_{2}$

we can make out which event has occurred only if $v_{1} = v_{2}$