Al colocar un objeto delante de una lente convergente se genera una imagen real invertida y de doble tamaño, sabiendo que dicha imagen se forma a 30cm delante de la lente, calcule la distancia focal.
Aumento Lente Convergente

30 cm

Explanation:

To solve this problem, we use the lens equation:

where

f is the focal length of the lens

p is the distance of the object from the lens

q is the distance of the image from the lens

In this problem, we know that

q = -30 cm is the distance of the image from the lens; it is negative because the image is formed in front of the lens, so it is a virtual image

We also know that the size of the image is twice that of the object, so the magnification is 2:

where M is the magnification of the lens. Solving this equation for p,

So, the distance of the object from the lens is 15 cm.

Now we can finally solve the lens equation to find f, the focal length:

see earlier answer

what is the speed of a softball that travels 20m in 2secs

speed = 20/2 = 10 m/s