Question: change direction of normal in PlotPositionVector

There are two normals to a point on a curve.  How do I get the PlotPositionVector of Student[VectorCalculus] to point in the other direction. 

with(Student[VectorCalculus]:

R1:=PositionVector([p,p^2],polar[r,t]):

PlotPositionVector(-R1,p=1..2,normal=true,points=[1.5])

 

The normal vector points towards the insided of the curve.  Can I use PlotPositionVector to have it point the opposite way (towards the outside of the curve)?

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