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A-man-standing-10m-away-from-a-plane-mirror-moves-towards-the-mirror-with-a-speed-of-2m-s-Calculate-a-The-speed-with-which-his-image-in-the-mirrow-approaches-him-b-How-far-is-the-man-from-his-ima




Question Number 221913 by Tawa11 last updated on 12/Jun/25
A man standing 10m away from a plane  mirror moves towards the mirror with a  speed of 2m/s. Calculate  (a) The speed with which his image in the  mirrow approaches him  (b) How far is the man from his image  after 3 seconds.
A man standing 10m away from a plane
mirror moves towards the mirror with a
speed of 2m/s. Calculate
(a) The speed with which his image in the
mirrow approaches him
(b) How far is the man from his image
after 3 seconds.
Answered by fantastic last updated on 12/Jun/25
a)2m/s  b) relative speed 2+2⇒4m/s  after 3 second distaece covered by both=4×3=12m  total distance 10+10=20m  so 20−12=8m
$$\left.{a}\right)\mathrm{2}{m}/{s} \\ $$$$\left.{b}\right)\:{relative}\:{speed}\:\mathrm{2}+\mathrm{2}\Rightarrow\mathrm{4}{m}/{s} \\ $$$${after}\:\mathrm{3}\:{second}\:{distaece}\:{covered}\:{by}\:{both}=\mathrm{4}×\mathrm{3}=\mathrm{12}{m} \\ $$$${total}\:{distance}\:\mathrm{10}+\mathrm{10}=\mathrm{20}{m} \\ $$$${so}\:\mathrm{20}−\mathrm{12}=\mathrm{8}{m} \\ $$
Commented by Tawa11 last updated on 12/Jun/25
Thanks sir.
$$\mathrm{Thanks}\:\mathrm{sir}. \\ $$
Commented by Tawa11 last updated on 12/Jun/25
(a)  So, since the object approaches 2m/s.  Image too will approach 2m/s.  I was adding    2 + 2  =  4m/s  before.
$$\left(\mathrm{a}\right) \\ $$$$\mathrm{So},\:\mathrm{since}\:\mathrm{the}\:\mathrm{object}\:\mathrm{approaches}\:\mathrm{2m}/\mathrm{s}. \\ $$$$\mathrm{Image}\:\mathrm{too}\:\mathrm{will}\:\mathrm{approach}\:\mathrm{2m}/\mathrm{s}. \\ $$$$\mathrm{I}\:\mathrm{was}\:\mathrm{adding}\:\:\:\:\mathrm{2}\:+\:\mathrm{2}\:\:=\:\:\mathrm{4m}/\mathrm{s}\:\:\mathrm{before}. \\ $$
Commented by fantastic last updated on 13/Jun/25
that 2+2 would be the velocity in which  they approach each other.[relative speed]    you asked the velocity of the image
$${that}\:\mathrm{2}+\mathrm{2}\:{would}\:{be}\:{the}\:{velocity}\:{in}\:{which} \\ $$$${they}\:{approach}\:{each}\:{other}.\left[{relative}\:{speed}\right] \\ $$$$ \\ $$$${you}\:{asked}\:{the}\:{velocity}\:{of}\:{the}\:{image} \\ $$
Commented by mr W last updated on 13/Jun/25
the image moves with a speed of  2 m/s towards him, or  the image approaches him with a  speed of 4 m/s.
$${the}\:{image}\:{moves}\:{with}\:{a}\:{speed}\:{of} \\ $$$$\mathrm{2}\:{m}/{s}\:{towards}\:{him},\:{or} \\ $$$${the}\:{image}\:{approaches}\:{him}\:{with}\:{a} \\ $$$${speed}\:{of}\:\mathrm{4}\:{m}/{s}. \\ $$
Commented by mr W last updated on 13/Jun/25
i think this is more a question of   “english language understanding”.  let′s let a native english speaker  judge.
$${i}\:{think}\:{this}\:{is}\:{more}\:{a}\:{question}\:{of}\: \\ $$$$“{english}\:{language}\:{understanding}''. \\ $$$${let}'{s}\:{let}\:{a}\:{native}\:{english}\:{speaker} \\ $$$${judge}. \\ $$
Commented by mr W last updated on 13/Jun/25
this is what ChatGPT answers:
$${this}\:{is}\:{what}\:{ChatGPT}\:{answers}: \\ $$
Commented by mr W last updated on 13/Jun/25
Commented by fantastic last updated on 13/Jun/25
r^(∗     ) elative^∗
$$\overset{\ast\:\:\:\:\:} {\boldsymbol{{r}elativ}}\overset{\ast} {\boldsymbol{{e}}} \\ $$
Commented by Tawa11 last updated on 13/Jun/25
Velocity of image of the man as observed  by the the man (object)  =  2  +  2  =  4m/s  What I think.
$$\mathrm{Velocity}\:\mathrm{of}\:\mathrm{image}\:\mathrm{of}\:\mathrm{the}\:\mathrm{man}\:\mathrm{as}\:\mathrm{observed} \\ $$$$\mathrm{by}\:\mathrm{the}\:\mathrm{the}\:\mathrm{man}\:\left(\mathrm{object}\right)\:\:=\:\:\mathrm{2}\:\:+\:\:\mathrm{2}\:\:=\:\:\mathrm{4m}/\mathrm{s} \\ $$$$\mathrm{What}\:\mathrm{I}\:\mathrm{think}. \\ $$

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