Question

Consider a frictionless track as shown in the figure below. A block of mass m₁ = 5.55 kg

 is released from . It makes a head-on elastic collision at  with a block of mass m₂ = 12.5 kg

 that is initially at rest. Calculate the maximum height to which m₁ rises after the collision.

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Answer 1

$v_1=\sqrt{2gh}=10~\frac ms,$

$\begin{cases} m_1v_1=-m_1u_1+m_2u_2, \\ \frac{m_1v_1^2}2=\frac{m_1u_1^2}2+\frac{m_2u_2^2}2, \end{cases}$ $\implies$

$u_1=v_1\frac{m_2-m_1}{m_2+m_1}=3.85~\frac ms,$

$h'=\frac{u_1^2}{2g}=0.74~m.$