Geostrophic Flow at 500 mb

When the flow is parallel to approximately straight height lines, the flow is geostrophic.

Q: what determines the strength of the geostrophic flow? ANSWER 

QUESTIONS FOR THOUGHT:

1.  Given a 40 knot geostrophic northwesterly wind at 500 mb, draw a diagram showing the orientation of the height lines necessary to create this wind.  Also draw in the directions and relative magnitudes of all forces acting on this air parcel.

2.  Now consider a 20 knot southeasterly wind at the surface.  Draw a diagram illustrating the orientation of the isobars necessary to create this wind and also draw in the direction and relative magnitudes of all forces acting on this parcel of air.

500 mb chart