imagine que você se encontra parado à frente de um espelho plano, que também se encontra em repouso. imagine agora que esse espelho passe a se deslocar com uma velocidade constante e igual a 10 m/s. neste caso a velocidade da imagem formada, em relação a você, que é o objeto fixo da situação, será igual a:

The speed of the image is changing with the same 10 m/s speed, in the direction of the mirror's motion.

Explanation:

For a flat mirror, it is known that the object distance is always equal to the image distance, this is proven from the mirror equation

(1/f) = (1/u) + (1/v)

f = focal length = ∞ (for a flat mirror, the focal length is theoretically imfinity)

v = image distance from the mirror

u = object distance from the mirror

For a flat mirror, (1/f) = (1/∞) = 0

0 = (1/u) + (1/v)

(1/v) = -(1/u)

v = -u

The minus sign means that the image distance is measured in the opposite direction to the object distance.

(dv/dt) = -(du/dt)

So, if the mirror starts moving at a particular speed, as long as the object doesn't move, the object's distance from the mirror is changing according to the speed of the mirror alas in the direction opposite the mirror's motion.

Hence, if (du/dt) = -10 m/s

(dv/dt) = 10 m/s

Meaning that the speed of the image is changing with the same 10 m/s speed, in the direction of the mirror's motion.

Hope this Helps!!!