A ball is dropped from rest 3.0 m directly above the vertex of a concave mirror that has a radius
of 1.0 m and lies in a horizontal plane.
(a) Describe the motion of ball's image in the mirror
(b) At what time do the ball and its image coincide?

Answer

A, B, C, D

Explanation

(a) From O to F, image is real
From f to P, image is virtual .

At `O 1/v+1/u=1/f`
`:. 1/v+1/(-3.0)=(1)/(-0.5)`
`v=-0.6m`
(b) When object is at C and P, image coincides with object .
Using
`s-(1/2)(g t^(2))`
or, `t=(sqrt((2s)/(g)))`
`At C t=(sqrt(2xx2)/(9.8))=0.639s`
`At P t=(sqrt(2xx3)/(9.8))=0.782s`.