Homework Help: Calculating vectors

1. Jan 12, 2012

bobsmith76

1. The problem statement, all variables and given/known data

Consider a nuclear reaction in which a neutron travelling 1.0 × 107 m/s in the +x direction collides with a proton travelling 5.0 × 106 m/s in the +y direction. They combine at impact to form a new particle called a “deuteron.” What is the magnitude of the deuteron velocity? Assume for simplicity that the proton and neutron have the same mass.

2. Relevant equations

a2 + b2 = c2

3. The attempt at a solution

I would think you would just use the pythagorean theorem to solve the problem. When you do that you get 1.1 * 107 The textbook says the answer is 5.6 * 106

2. Jan 12, 2012

Staff: Mentor

You'd use the Pythagorean theorem to add the two momenta. But how would you solve for the new velocity?

3. Jan 12, 2012

bobsmith76

But if their mass is the same then the momentum should equal the velocity. In the equation

p = mv

If m = 1, then p should equal v

4. Jan 12, 2012

Staff: Mentor

If the mass of each original particle is '1' unit, what's the mass of the new combined particle?

5. Jan 12, 2012

bobsmith76

Thanks, I got it. I really appreciate your help.