A point object is moving uniformly towards th | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(C) Given: Focal length $f = -25 \ cm$. Initial object distance $u_i = -50 \ cm$. Speed of object $v_o = 1 \ ms^{-1} = 100 \ cm s^{-1}$.At $t=0$,$u_i

Vedclass · Accepted Answer

infinity

Vedclass · Answer

(C) Given: Focal length $f = -25 \ cm$. Initial object distance $u_i = -50 \ cm$. Speed of object $v_o = 1 \ ms^{-1} = 100 \ cm s^{-1}$.At $t=0$,$u_i = -50 \ cm$. Using mirror formula $\frac{1}{v} + \frac{1}{u} = \frac{1}{f}$,we get $\frac{1}{v_i} + \frac{1}{-50} = \frac{1}{-25} \implies \frac{1}{v_i} = -\frac{1}{25} + \frac{1}{50} = -\frac{1}{50} \implies v_i = -50 \ cm$.At $t=0.25 \ s$,the distance moved by the object is $d = v_o 	imes t = 100 \ cm s^{-1} 	imes 0.25 \ s = 25 \ cm$.New object distance $u_f = -50 \ cm + 25 \ cm = -25 \ cm$.Since the object is at the focus,the image is formed at infinity,i.e.,$v_f = \infty$.The average velocity of the image is $\langle v angle = \frac{v_f - v_i}{\Delta t} = \frac{\infty - (-50)}{0.25} = \infty$.

Similar Questions

$A$ convex mirror of focal length $20 \, cm$ is fitted in a car. $A$ second car,which is $2.8 \, m$ away,overtakes the first car at a relative speed of $15 \, m/s$. What will be the speed of the second car as observed in the mirror of the first car?

$A$ car is fitted with a convex side-view mirror of focal length $20\ cm$. $A$ second car $2.8\ m$ behind the first car is overtaking the first car at a 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

An object approaches a convex mirror of radius of curvature $20 \,m$ along its optical axis. The image is observed to move from $\frac{25}{3} \,m$ to $\frac{50}{7} \,m$ from the mirror in $30 \,s$. What is the speed of the object in $km/h$?

$A$ plane mirror is moving with velocity $4\hat i + 5\hat j + 8\hat k$. $A$ point object in front of the mirror moves with a velocity $3\hat i + 4\hat j + 5\hat k$. Here,the $\hat k$ direction is along the normal to the plane mirror and facing towards the object. The velocity of the image is:

Vedclass Test Series

Exam Paper Generator

Online Exam Module