A girl stands 5m away from a large plane mirror. How far must she walk to be 2m away from her image?

The girl needs to walk 4m closer to the mirror if she must be 2 m away from her image.

Explanation:

Images formed by plane mirrors is due to reflection of light Plane mirrors form only virtual or imaginary images. The image formed by a plane mirror is equidistant from the mirror as the object is from the mirror. This means that the distance of the girl from the mirror which is 5m is equal to the distance of her image from the mirror.

The distance of the girl from her image when she stands 5 m from the mirror is therefore, 5m + 5m = 10 m

In order for her to be 2 m away from her image, she needs to sand at a distance half her distance from her image, that is 1/2 * 2m = 1m

Therefore, the girl needs to walk 5m - 1m = 4m closer to the mirror if she has to be 2 m away from her image.

initial speed when it is dropped is 150 ft/s

now at the same moment the acceleration due to gravity is perpendicular to its velocity

so as we know that

now we have centripetal acceleration a = 32 ft/s^2 as its perpendicular to velocity

while tangential acceleration at the same moment will be zero

so

now radius of curvature is given as

so the radius of curvature just after it is dropped is 703.125 ft