Flag Engineering Entrance Exams> A car is fitted with a convex side-view m...
question mark

A car is fitted with a convex side-view mirror of focal length 20cm. A second car 2.8 m behind the first car is overtaking the first car at relative speed of 15 m/s. The speed of the image of the second car as seen in the mirror of the first one is

sudhanshu , 11 Years ago
Grade 12
anser 2 Answers
Saurabh Koranglekar

Last Activity: 5 Years ago

576-1852_2.PNG

Vikas TU

Last Activity: 5 Years ago

From mirror formula (using convex mirror)
1/u+1/v=1/f …(i)
Using u=−2.8m=−280cm,f=20cm
∴1/−280+1/v=1/20or1/v=1/20+1/280=15/280
or v=280/15cm
Differentiating (i) w.r.t t, we have
−1/u2du/dt−1/v2dv/dt=0 or dv/dt=−v2/u2(du/dt)
∴ Relative velocity of image,
v1=dv/dt=−v2/u2(du/dt)=−(280/152)/(−280)2×15
=−1/15m/s

star
LIVE ONLINE CLASSES

Prepraring for the competition made easy just by live online class.

tv

Full Live Access

material

Study Material

removal

Live Doubts Solving

assignment

Daily Class Assignments



question mark
consider the figure of a single riveted lap joint as follows
engineering entrance exams
0 Answer Available

Last Activity: 3 Years ago

question mark
Hello,
 
Can we learn and prepare for MHT-CET online ?
engineering entrance exams
0 Answer Available

Last Activity: 3 Years ago