| Perfectly Elastic | Perfectly Inelastic |
| K.E. is conservedColliding objects do not stick together after collisionIn case of head-on collision directions of the bodies are reversed | K.E. decreasesColliding objects stick and move together after collisionDirection of both bodies may or may not be reserved |
(b)
(c)(i) Stage 1; S = ut + \(\frac{1}{2}at^2\)
= 120 = 0 x 12 + \(\frac{1}{2}\) x a x 12\(^2\)
a = \(\frac{5}{6}\)
\(V_1 = u + at\)
= 20 + \(\frac{5}{6} \times 12 = 30m/s\)
Stage 3; S = ut + \(\frac{1}{2}\) at\(^2\)
-180 = 30 x 12v + \(\frac{1}{2}\) x a x 12\(^2\)
a = \(\frac{-5}{2}\)
V\(_3\) = u + at = 30 + \(\frac{-5}{2}\) x 12 = 0m/s
(ii) v/m\(^{s - 1}\)
