4. Consider an unstable particle with a mass M = 3.34 x 10-2 kg. We can use the inertial frame of the unstable particle, so the initial velocity of the particle is zero. Suddenly, the particle decays into two fragments. Fragment 1 travels left with a speed of 0.987c and Fragment 2 travels right with a speed of 0.868c. Find the mass of Fragment 1 and Fragment 2. 5. Massless particles, such as a photon, have energy given by E = pc where p is the momentum (yes, electromagnetic waves have momentum, we'll discuss this in more detail VERY soon). Show that a photon cannot be completely absorbed by a free electron. You can think of this as a collision between an electron and photon where in the final state only the electron remains. Use conservation of energy and momentum to show that this is not possible