Dear Megan,
we tried your code, but when we pasted it in Mathemtica it broke and did not work. It also contained mixed pieces of text and generally was very large and very hard to work with. Our advice is is to come up with a smaller simpler self-sufficient working code that pinpoints your issue. If you have a few issues - you can ask a few different questions.
Also please take a look at the Wolfram Demonstrations Project for many example of working animations. The source code is available for download there and you can adopt it to your own problem. There are many demonstrations there that you can look at. For instance:
Frictional Force on a Car in a Turn
Manipulate[
Grid[{{Graphics[{Gray, Disk[{0, 0}, r + 7, {-\[Pi]/4, \[Pi]/4}],
RGBColor[.6, .73, .36], Disk[{0, 0}, r, {-\[Pi]/4, \[Pi]/4}],
RGBColor[.49, 0, 0],
Rotate[{Polygon[{{r + .5, -2}, {r + .5, 2}, {r + 2.5,
2}, {r + 2.5, -2}}], Yellow,
Disk[{r + .7, 2}, .1, {0, \[Pi]}],
Disk[{r + 2.3, 2}, .1, {0, \[Pi]}],
Disk[{r + .7, -2}, .1, {\[Pi], 2 \[Pi]}],
Disk[{r + 2.3, -2}, .1, {\[Pi], 2 \[Pi]}], Gray,
Polygon[{{r + .75, .55}, {r + .55, .85}, {r + 2.4, .85}, {r +
2.2, .55}}],
Polygon[{{r + .75, -.55}, {r + .55, -.85}, {r +
2.4, -.85}, {r + 2.2, -.55}}],
Polygon[{{r + .55, -.7}, {r + .55, .7}, {r + .75, .45}, {r + \
.75, -.45}}],
Polygon[{{r + 2.4, -.7}, {r + 2.4, .7}, {r + 2.2, .45}, {r +
2.2, -.45}}], Blue, Arrow[{{0, 0}, {r + 1.5, 0}}],
Text[Style["r", 18, Italic], {r - 1, .5}],
Arrow[{{r + 1.5, 0}, {r + 1.5, 1.5}}],
Arrow[{{r + 2.5, 0}, {r + 1.5, 0}}], White,
Text[Style["v", 18, Italic], {r + 1.5, 1.75}], Black,
Text[
Style["\!\(\*SubscriptBox[\(f\), \(s\)]\)", 18,
Italic], {r + 3, 0}]}, \[Theta], {0, 0}]},
PlotRange -> {{r - 4, r + 8}, {-8, 8}}, Background -> LightGray,
ImageSize -> 300], Spacer[5],
Text@Style[
Column[{"centripetal acceleration:",
Row[{NumberForm[( 10/36. v)^2/r, {3, 2}],
" m/\!\(\*SuperscriptBox[\(s\), \(2\)]\)"}],
"", "force needed:",
Row[{NumberForm[(m 10/36. v)^2/r, {3, 2}], " N "}], "",
"minimal static friction\ncoefficient:",
NumberForm[m (10/36. v)^2/(9.81 m r), {3, 2}]}, Spacings -> 2,
Alignment -> Center], 14, Purple, Bold]}}], {{r, 50}, 20, 100,
Appearance -> "Labeled"}, {{\[Theta], -.04}, -ArcSin[6/r] ,
ArcSin[6/r], Appearance -> "Labeled" }, {{v, 60}, 35, 120,
Appearance -> "Labeled"},
{{m, 1050}, 850, 1200, Appearance -> "Labeled"}]
