Review question

# If we know the object's speed, can we find the speed of the image? Add to your resource collection Remove from your resource collection Add notes to this resource View your notes for this resource

Ref: R8625

## Question

The distances $u$ and $v$ of an object and its image respectively from a lens of focal length $f$ are connected by the formula $\begin{equation*} \frac{1}{u} + \frac{1}{v} = \frac{1}{f}. \end{equation*}$

Determine the speed of the image of an object when the object is $\quantity{3}{m}$ from a lens of focal length $\quantity{\dfrac{1}{2}}{m}$ and is moving away from the lens at $\quantity{5}{m\,s^{-1}}$.