Do Neutrinos Leave Tracks in Cloud Chambers?

[colemc20]

Homework Statement

A radioactive nucleus at rest decays into a second nucleus, an electron, and a neutrino. The electron and neutrino are emitted at right angles and have momenta of 9.40 ✕ 10-23 kg·m/s, and 5.10 ✕ 10-23 kg·m/s, respectively. What is the magnitude and direction of the momentum of the second (recoiling) nucleus?
Magnitude ___ kg·m/s
Direction ___ ° (measured from the direction opposite to the electron's momentum)

Relevant Equations

Conservation of Momentum

My only issue is what this would look like. I can't draw a respective picture.

 

[scottdave]

Momentum is a vector. Suppose the electron is moving East and the neutrino is moving North. What is opposite of East? Find the angle relative to that.

 

[kuruman]

My only issue is what this would look like. I can't draw a respective picture.

Three vectors that add to zero form a closed triangle when you add them using the tip-to-tail graphical method of vector addition. Furthermore, this is a right triangle with the unknown vector as the hypotenuse. So draw a right triangle with right sides 9.4 and 5.1 and the needed hypotenuse, put arrowheads tip to tail at the vertices and then move the vectors parallel to themselves so that their tails are all at the same point. Voila, you have your picture. N.B. the original position of the parent radioactive nucleus is where the tails meet.

 

[jbriggs444]

Three vectors that add to zero form a closed triangle when you add them using the tip-to-tail graphical method of vector addition.

I agree that a picture as a triangle denoting tip-to-tail addition of three vectors is a good way to graphically calculate the unknown third vector.

However, for a "what would this look like" diagram, I would be more inclined to draw something akin to a set of cloud chamber tracks -- a mark in the center where the decay took place and three tracks extending outward corresponding to the three daughter particles. To tie it back to a momentum calculation, one would still want to set the length and direction of each track based on the momentum of the corresponding daughter particle.

 

[kuruman]

Do neutrinos leave tracks in cloud chambers?

 

[jbriggs444]

Do neutrinos leave tracks in cloud chambers?

Nope. Hence the "something akin to".