A8.0 kg shell leaves a 2.0 x 103 kg cannon, at a speed of 4.0 x 102 m/s. what is the recoil speed of the cannon?

Perhaps seek some professional ? it isn't very asking some children who are just trying to find out answers to homework.also, it seems professional would actually be good to you. obviously it isn't going to magically fix your depression, but it'll do something. drugs, smoking weed, it won't do much, especially if your husband is against it. if you do it he'll dislike it. but talk to him, try and get him to listen to you, and figure everything out together, okay? there's a website- maybe it can offer some ?

Iwas thinking the wavelength is one half its original value

The answer is n = 2  and    n = 3