Particle 1 of mass 200 g and speed 3.00 m/s undergoes a one-dimensional collision with stationary particle 2 of mass 400 g. What is the magnitude of the impulse on particle 1 if the collision is (a) elastic and (b) completely inelastic?
Using Eq. 9-67, we have after the elastic collision
v_{1 f}=\frac{m_1-m_2}{m_1+m_2}v_{1 i} (9-67)
v_{1 f}=\frac{m_1-m_2}{m_1+m_2}v_{1 i}=\frac{-200 \,g}{600\, g}v_{1 i}=-\frac{1}{3}(3.00\, m / s )=-1.00 \,m / s .
(a) The impulse is therefore
or |J| = -0.800 kg.m/s.
(b) For the completely inelastic collision Eq. 9-75 applies
v_{1 f}=\frac{m_1-m_2}{m_1+m_2}v_{1 i}+\frac{2 m_2}{m_1+m_2}v_{2 i} (9-75)
v_{1 f}=V=\frac{m_1}{m_1+m_2}v_{1 i}=+1.00 \,m / s.
Now the impulse is
.