Question

A car fitted with a convex side view mirror of $f=20cm$ A $2nd$ car $2.8m$ behind the $1st$ car is overtaking the 1st car with a relative speed of $15m/s$ what will be the speed of $2nd$ car w.r.t first one?

Answer 1

F=$20cm=0.2m$
Speed of $2nd$ cur =v=$25m/s$
relative speed of merge of $2nd$ cent
$m=\frac{f}{f.4}=\frac{0.2}{0.2-(-2.8)}$
$=\frac{0.2}{3}=\frac{1}{5}$
$\frac{v^{\prime }}{v}=m^2$
$v^{\prime }=15\times \frac{1}{225}=\frac{1}{15}m/s$