Answer
The momentum of block 3 is greater than the initial momentum of block 1
Work Step by Step
We can find an expression for the initial momentum of block 1:
$p_1 = m_1~v_1$
$p_1 = m_1~(4.00)$
$p_1 = 4.00~m_1$
In part (a), we found that the speed of block 3 is $1.78~m/s$
Note that $m_3 = 4.00~m_1$
We can find an expression for the momentum of block 3:
$p_3 = m_3~v_3$
$p_3 = (4.00~m_1)~(1.78)$
$p_3 = 7.12~m_1$
The momentum of block 3 is greater than the initial momentum of block 1.
