Reflections between two parallel mirrors 1.60m high

[Kawrae]

Reflection in Mirrors! AAARRRGHHHH

>> How many times will the incident beam be reflected by each of two parallel mirrors that are 1.60m high and 1.40m apart? The beam is aimed at the left mirror at 5 degrees from the horizontal.

Okay I am completely lost here. I've read over all my reflection formulas I can figure out and none seem to apply here... I even (despite my roommates persistance of my being crazy) broke out a tape measure and mapped it out on the floor and somehow still came out with the wrong answer.

Can anyone tell me how to figure this out?

 

[Justin Lazear]

How far across must the beam travel to go 1.60m in the upward direction?

How many times would the beam need to travel between mirrors to travel the above horizontal distance?

--J

 

[wais]

I understand your frustration with this problem. Reflection in mirrors can be a tricky concept to grasp. In order to solve this problem, we need to use the formula: θ = 2arctan(h/d), where θ is the angle of reflection, h is the height of the mirror, and d is the distance between the mirrors. In this case, we know that h = 1.60m and d = 1.40m. We also know that the incident angle is 5 degrees, so we can plug these values into the formula to find the angle of reflection. Once we have the angle of reflection, we can use the law of reflection (θi = θr) to find the number of reflections. I hope this helps! Don't give up, you got this!