Correct typo 'if' -> 'of' for S&Jv8 P9.9.

diff --git a/latex/problems/Serway_and_Jewett_8/problem09.09.tex b/latex/problems/Serway_and_Jewett_8/problem09.09.tex
index c36e4b25ace6006285e169fe4c8f1febe4bd9e8e..be48d65b618c8eee8d3f70ee74a32acbaa89ee8e 100644 (file)
--- a/latex/problems/Serway_and_Jewett_8/problem09.09.tex
+++ b/latex/problems/Serway_and_Jewett_8/problem09.09.tex
@@ -3,7 +3,7 @@ Two blocks of mass $m$ and $3m$ are placed on a frictionless,
 horizontal surface.  A light spring is attached to the more massive
 block, and the blocks are pushed together with the spring between them
 (Fig.~P9.9).  A cord initially holding the blocks together is burned;
-after that happens, the block if mass $3m$ moves to the right with a
+after that happens, the block of mass $3m$ moves to the right with a
 speed of $2.00\U{m/s}$.  \Part{a} What is the velocity of the block of
 mass $m$?  \Part{b} Find the system's original elastic potential
 energy, taking $m=0.350\U{kg}$.  \Part{c} Is the original energy in