(a)[2]
State the principle that momentum is conserved.
(b)
A stationary firework bursts into three separate fragments that travel in a horizontal plane, as shown in Fig. 2.1. The fragment of mass $3.0M$ has a velocity of $7.0\,\text{m s}^{-1}$ perpendicular to line AB. The fragment of mass $2.0M$ has a velocity of $6.0\,\text{m s}^{-1}$ at angle $\theta$ to line AB. The fragment of mass $1.5M$ has a velocity of $8.0\,\text{m s}^{-1}$ at angle $\theta$ to line AB.
(b(i))[3]
Use the principle of conservation of momentum to find $\theta$.
(b(ii))[2]
Calculate the ratio $\frac{\text{kinetic energy of fragment of mass } 2.0M}{\text{kinetic energy of fragment of mass } 1.5M}$.