Change in momentum =
\(\begin{array}{l} \Delta \vec{P} \end{array} \)
=
\(\begin{array}{l} \Delta P_{x}\hat{i} + \Delta P_{x}\hat{j} \end{array} \)
Since
\(\begin{array}{l} \Delta P_{x} = 0 \end{array} \)
\(\begin{array}{l}\Delta P_{y}\hat{j} = \vec{P}_{fy} – \vec{P}_{iy} \end{array} \)
\(\begin{array}{l}P_{iy} = mvsin45 and P_{fy} = mvsin45 \end{array} \)
=
\(\begin{array}{l} – 2mvsin45 = -\sqrt{2}mv_{j}\left | \Delta = \vec{P} \right | \end{array} \)
=
\(\begin{array}{l} \sqrt{2}mv \end{array} \)
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