A radioactive nucleus of mass 5 × 10–26 kg is at rest and emits two neutrons, each of mass 1.6 × 10–27 kg, at right angles to each other. If both have speeds of 360 m s–1, calculate the recoil speed of the nucleus. I named calculated the neutrons and named them p1 and p2. Since p1 = p2 Therefore the momentum of both equals 1.8x10-26 Using Pythagoras, I worked out the overall momentum to be 2.55x10-26 I then used the formula m1v1 = m2v2 and worked out the velocity to be 509-510ms-1; I didn't bother working out the angle because that was already the wrong answer. The real answer is 17.39ms-1. What have I done wrong? Thanks in advance.