Image of an object approaching a convex mirror of radius of curvature 20 m along its optical axis is observed to move from \frac{25}{3} m \textrm{ }\textrm{ } to \frac{50}{7} m in 30 seconds. What is the speed of the object in km per hour?

Engineering

Physics

Physical Quantities

Question

Image of an object approaching a convex mirror of radius of curvature 20 m along its optical axis is observed to move from $\frac{25}{3} m to \frac{50}{7} m$ in 30 seconds. What is the speed of the object in km per hour?

LiveFree JEE Main Previous Year Online Papers Live Free JEE Advance Previous Year Online Papers

College PredictorLive

Know your College Admission Chances Based on your Rank/Percentile, Category and Home State.

Get your JEE Main Personalised Report with Top Predicted Colleges in JoSA

$v = \frac{25}{3}$

$\frac{1}{v} + \frac{3}{25} = \frac{1}{10}$

$\frac{1}{v} = \frac{1}{10} - \frac{3}{25} = \frac{25 - 30}{250} = \frac{- 5}{250}$

u₂ = – 50

$\frac{1}{v} + \frac{7}{50} = \frac{1}{10} = \frac{1}{v} = \frac{1}{10} - \frac{7}{50} = \frac{5 - 7}{50} = - 25$

$vel . obj . = \frac{25}{30} m / s = \frac{25}{30} \times \frac{18}{5} = 3 km / hr$

Please subscribe our Youtube channel to unlock this solution.